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,'Sil.,., Sp..lw;~, !:'·' ·~1::,~ ·.·~·
PROJECT PANDORA (U)
Final Report
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MRT-4-046 QM-66-072 DRC- H- 9331- oO ;(,.,
,
2 " F;::: R 167. 7., ... - -· ! ... :
Prepared by
Eug~ne V. Byron
November 1966
·~ .. / .,. J.ohn• H:::>pki,..,unrw.nity &.li'i1PHYStC. l.AaOAATO•Y ~it..,., Spri;-9, Metyland .
11!6R£ I MRT-4-046 QH-66-072
ABSTRACT
This is the final report on the Applied Physics Laboratory's
contribution to Project PANDORA - specifically, aid in the implementa
tion, and the evaluation of a microwave test facility at Walter Reed
Army Institute of Research. An "expandable" conical horn transmitting
antenna, and monitor dipole receiving antennas were designed for use in
the anechoic chamber constructed by Emerson and Cuming, Inc. A mechan
ical field traversing mechanism was designed and constructed for the
chamber evaluation, the microwave equipment was fun~tionally assembled,
and the completed facility was thoroughly evaluated. The evaluation
ncluded the mea3urement of power variations in the quiet zone with and
without the sample container (with and without the test sample) in the
required position, and the measurement of the power density in the quiet
zone usi~g the Microwave Associates high power TWT and the appropriate
transmitting horn sections.
,
. Th.:'Johnt HOI)kiill Ur~i...,ity .. • ~f01'1.1£D I"ICYIICS LAM•ArO•T liZ I
s;r.,., Sptir.g, M~ryleftd MRT-4-046 QM-66-072
TABLE OF CONTENTS
Section Title Page
I INTRODUCTION 1
II DESCRIPTION OF TilE MICROWAVE FACILITY 2
A .MICROWAVE ANECHOIC CHAMBER 2
B MICROWAVE EQUIPMENT 3
c TRANSMITTING HORN 4
"'' D POWER MONITORING 4
1 Transmitted Power Monitor 4
2 Standard Gain Horn Monitor 5
3 Monitor Dipole 6
E SELECTION OF TRANSMITTING HORN SECTIONS 6
1 Design Frequency Range 6
2 Horn Sections for Higher Power Densities 8
F DETERMINATION OF POWER DENSITY 8
III EVALUATION: PROCEDURE AND RESULTS 9
A MICROWAVE CHAMBER EVALUATION 10
B EVALUATION OF THE TEST SAMPLE CONTAINER, A~TD 13
THE TEST SAMPLE IN THE CONTAINER
1 Test Sample Container 13
2 Evaluation Procedure 13
3 Test Sample 14
c POWER DENSITY MEASUREMENTS 15 I
D CONCLUSION 16 !
I
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Section
APPEl\TDIX. ~
APPENDIX B
APPENDIX C
TABLE OF CONTENTS (continued)
Title
TRANSMITTING .HORN, DESIGN AND TEST RESULTS
SLEEVE DIPOLt ANTENNA
FIELD TRAVERSING MECHANISM
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LIST OF ILLUSTRATIONS
Figure No. Title
1 Micrmvave Anechoic Chamber
2 Microwave Anechoic Chamber - General
Arrangement Drawing
3 Rack Arrangement of Microwave Equipment
4 P~ndora Microwave Equipment - Functional
Block ·Diagram
5 Expandable Conical Horn
6 Absolute Gain of Conical Horn
7 E Plane 3 db Beamwidth of Conical Horn
8 H Plane 3 db Beamwidth.of Conical Horn
9 Typical E and H Plane Patterns of Conical Horn
10 High Power TWT Monitor - Meter Reading vs.
Transmitted Power
11 Power Density per Watt Transmitted for Each
Horn Section
12 Received Power Density, Monitor Channel No. 1
13 Monitor Dipoles
14. Change in Relative Amplitude for Various Fixed
Angles vs. Frequency; Horn S~ctions Dl to D6
15 Change in Relative Amplitude for Various Fixed
Angles vs. Frequency; Horn Sections D7 to DlO
16 Typical Reflection from Chamber Walls
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
HRT-4-046 cy-1-66-072
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19
20
21
·22
23
24
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LIST OF ·.ILLUSTRATIONS (continued)
Title
Chamber Evaluation - Frequency - 2.6 GHz 33
Chamber Evaluation - Frequency - 2.8 GHz 34
Chamber Evaluation - Frequency - 3.0 GHz 35
Chamber Evaluation Frequency 3.25 GHz
Chamber Evaluation - Frequency - 3.25 GHz (with Standard Gain Horn)
Chamber Evaluation Frequency 3.45 GHz
Chamber Evaluation Frequency 3.8 GHz
36
37
38
39
Field Perturbations Due to Sample Container 40
Sleeve Dipole Antc:nna B2
"Gooseneck" Monitor Dipole B3
VSWR of Dipole Antennas B4
Field Traversing Mechanism C2
Wiring Diagram, Field Traversing Mechanism C3
1111&CM£1• NRT-4-046 QH-66-072
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Table No.
1
2
3
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A2
A3
LIST OF TABLES
Title
Quiet Zone Volumes and Power Variations
Surmnary of Sample Cortainer Perturbations
Measured versus Calculated Power Densities
Transmitting Horn Dimensions
Measured versus Calculated Gain
Measure-d versus Calculated E & H Plane Beamwidths
aii!GIIEF MRT-4-046 QM-66-072
Page
11
14
15
A3 .,
A4
A5
· .. Th• John• H01)kin1 Ul'll..,.,.lty
APPLilO .. Hl'IIU UMIATOR'I Sil......, ~irof, MMyleftd
I. INTRODUCTION
This is the final report on the contribution of the Johns
Hopkins University Applied Physics Laboratory, to Project PANDORA -
specifically, aid in the implementation and the evaluation of a micro
wave test facility at the Walter Reed Army Institute of Research, Forest
Glen Section. APL 1 s responsibilities were divided into roughly three
areas: (1) aid in determining the suitability of the microwave equip
ment to be procured, and the functional assembly of this equipment (2)
the design and fabrication of necessary specialized equipment,· - trans
mitting horn, monitoring dipole antennas, a field traversing mechanism, ,
etc., and (3) the evaluatJort' of the microwave anechoic chamber, the
calibration of the measurement equipment, and the test of the completed
facility. The test and evaluation of the completed facility included
the measurement of the power variations in the quiet zone of the anechoic
chamber with and without the sample container (with and without the test'
sample) in the required position, and the measurement of the power den
sity in the quiet zone.
In addition, a familiarization session was conducted for Army (1)
personnel scheduled to operate the facility. A companion report de-
scribes the operational procedure, the procedure for determining the
power requirements and which "add-on" section of the expandable conical
horn to use for a desired power density, and a description of the moni
toring equipment.
The commerically available microwave equipment was specified
and purchased by the Air Force Avionics Laboratory (AFAL), Wright-Patterson
AFB, Columbus, Ohio - the· program managers. The microwave anechoic chamber
was designed and constructed by Emerson and Cuming, Inc., Canton, Mass.
The high power microwave traveling wave tube was designed and built by
Microwave Associates, Burlington, }~ss., with the associated power supplies
furnished by Alto Scientific, Inc., Palo Alto, California.
(1) "Operational Procedure for Project PANDORA Nicrowave Test Facility11
APL/JHU Report 'MRT-4-045; (QH-66-071) dated October 1966 (U)
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II. DESCRIPTION OF THE MICROWAVE FACILITY
The microwave test facility implemented at Walter Reed con
sists of a microwave anechoic chamber, an expandable conical transmit
ting horn attached to one end wall of the chamber, and the microwave
control and monitoring equipment installed in four equipment racks
which are housed in the control room adjacent to the transmission end
of the chamber. Also, a standard gain horn power monitor, and two
sleeve dipole monitoring antennas are installed in the microwave chamber.
The facility was designed to operate at S-Band, with conver- , sion potential through X-Band, such that a suitable quiet zone - minimum
dimensions, 3' wide x 2' high x 1' deep, fo.r: two 'test samples side by
side- would be illuminated uniformly; a power.density of 2 mw/cm2 ± 1.0 db
over the frequency band was the design goal, with a potential for a power
density of 10 mw/cm2 over a reduced volume and ai fixed frequency.
A. MICROWAVE ANECHOIC CHAMBER
The microwave anechoic chamber (Eccosorb Anechoic Chamber No.
650) is approximately 15' wide by 15' high by 35' long. The proposed
four foot cubic quiet zone is symmetric about a point 25 fee~ from the
tra~.~mitting end wall, and equidistant between the floor, ceiling and
side walls. Figure 1 is a photograph of the chamber; figure 2 is the
general arrangement drawing, and also. shows the mounting detai 1 for the
transmitting horn.
The design requirements for the chamber specified that the power
variations should not exceed.± .25 db superimposed on the transmitted gain
"droop" measured in the quiet zone.with an absorber backed dipole over the
frequency band of interest. As noted in Section III of this report, ·
these values were not realized, and power "amplitude ripples" as great as
± 1.0 db were observed. The chamber evaluation showed that for the minimum
· quiet zone dimensions- 3' wide x 2' high x 1' deep, - power variations of
.•
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± 1. 75 db "Were possible over the S-Band frequency range. When a stan
dard gain horn "Was used as the field probe instead of the absorber backed
dipole, considerable improvement "Was observed; amplitude ripples were·less
than± 0.25 .db. This is discussed further in Section III.
B. MIC.ROWAVE EQUIPNENT
The microwave equipment is assembled in the four racks shown in
figure 3. Equipment rack number on~ contains the Spectrum Analyzer R. F.
and Display sect ions. Rack. number ;'Wo contains the auxiliary low. power
micro"Wave. generation and modulation equipment, and some ancillary equi~-., ment, in addition to the control panel for the field traversing mechanism.
Rack number three contains the primary lo'W-power microwave generation and
modulation equipment, and the necessary monitoring and recording equip:..
ment. Rack number four contains the high power microwave amplifier and
associated po'Wer supplies and R. F. power monitors.
The equipment in rack number t'WO is not interconnected (nor is
the spectrum analyzer). The interconnection of racks number three and four
'With the expandable conical horn is shown in figure 4 "Which is a functional
block diagram of the micro"Wave system. Also shown in this figure are the
"do"Wnstream" po"Wer monitors in the anechoic chamber.
All of the equipment assembled in racks number t"Wo and three are
cormnercial ''off the shelf" units (traveling mechanism control panel ex
cepted) and constitutes the best and most versatile, in terms of possible
R. F. modulations, microwave equipment available. This 'Was particularly
necessitated by the unkno'Wn nature of the desired signal for an experimental
facility. These units "Were specified and purchased by the program managers
(AFAL). Compatability and suitability of this equipment 'Was monitored by
APL and the equipment "Was functionally assembled and tested at APL and .de
livered as a unit to Walter Reed.
The high po"Wer microwave amplification equipment in rack four
was purchased under separate contract (from AFAL) to Microwave Associates
and 'WaS delivered as a unit.
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C. TRANSMITTING HO&.~
The transmitting horn characteristics were dictated by the
dimensions of the quiet zone to be upiformly illuminated. This de
sign rationale and the test results are discussed in Appendix A of this
.report. In order to provide a constant gain and beamwid th over the de
sired fr~quency band, "add-on" sections were provided as depicted in
figure 5.
The first section of this "expandable" conical horn incor
porates a rectangular to circular transition obviating the need for a
separate rectangular to circular waveguide transition.
Gain measurements and antenna patterns· were taken for each
horn section at the center, and at the low and high ends of the S-Band
frequency range. The results of these measurements are summarized in
figures 6, 7, 8,, and 9. Figure 6 shows the absolute gain of each of
the sections across the frequency band. Also shown, is the design fre
quency range for eacb s·ection. Figures 7 and 8 show the E and H plane
3 db beamwidth respectively, and figure 9 is a typical E and H plane
pattern (section D3) in its design frequency range.
D. POWER MONITORING
,
One of the prime requirements for the microwave test facility
was the ability to accurately determine the power density in the quiet
zone of the anechoic chamber and to observe the transmitted signal, within
the limits afforded by commercially available test equipment.
Three monitoring channels were incorporated in the system, and
several couple~ outputs are available for observing signal wave form,
either on an oscilloscope (detected outptits), or directly on the _spectrum
analyzer (see figure 4).
1. Transmitted Power Monitor
To measure .the transmitted power, two coaxia 1 direc tiona 1 couplers
and a thermistor mount were installed in the high power equipment rack (fig
ur~ 4). The thermistor output is connected to the HP 431C power meter in
rack number three. The loss in this coupled transmission path was measured
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MGaSIN 1-lRT- 4-046 QM-66-072 Page 5
over the 5-Band frequency range. The resultant calibration was incor
porated with the measured loss of the output cable and the waveguide to
coax adapter on the trans~itter horn, to plot the transmitted power curve
shown in figure 10. This curve is a plot of corrected power meter reading
versus transmitted power. Included in this figure is the legend for deter
minins tr~nsmitted power from the corrected meter reading, and conversely,
the method for setting the·transmitLed power by observing the meter reading.
This figure in conjunction with figure 11 (Power Density per Watt Trans
mitted for Each Horn Section) can be used to determine the on boresight
power density in the quiet_ zone. This is explained in greater detail in,
section II E.
2. Standard Gain Horn Monitor
The standard gain horn monitor (monitor number 1 in figure 4),,
is the primary "downstream" power density monitor. The gain deviation ver
sus frequency curve of the standard gain _horn, and the measured loss of the
connecting cable and waveguide to coaxial adapter were incorporated into
one frequency correction curve, shown in figure 12. This·figure is a plot
of the power density as a function of the corrected power meter reading.
The power density thus measured is the power density at the_ position where
the standard gain horn is placed in the chamber, and not the on boresight
power density alluded to in the section above. It is possible to measure
the power density i~ the anechoic chamber directly, only if the horn moni
tor can be physically placed at the desired position without interfering
with the experiment in progress. If this is not possible, then the power
density can be determined by extrapolating the measured power density, to
the power density at any other position in the quiet zone by using the
known gain-beamwidth characteristics of the transmitting horn section. In
a similar fashion, the on boresight power density determined from the meas
ured transmitted power can be extrapolated to any point in the quiet zone.
The determination of power density for other than on boresight (and meas
'lred) conditions is discussed in Section II F.
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3. Monitor Dipoles
In addition to the standard gain horn monitor, two sleeve di
pole monitors are available in the chamber for the observation of signal
waveforms. ·These dipole monitors are shown in figure 13. , The design
dimensions and the measured results are discussed in Appendix B.
·It was originally intended that these dipoles would be cali
brated ~nd used to measure. the abso~ute power density at any position in
the chamber. Unfortunately, the rather large amplitude ripples caused by
the reflections from the chamber walls, precluded this possibility. (The
standard gain horn integrates the ripples over its considerably larger , area and, consequently, was substituted as the prime power density monitor.)
However, since the dipoles are light-weight and easily movable, they were
retained for signal waveform observation, and for the "gross measure" of
power density. Since the two monitors have identical characteristics, by·
'lacing one at a region of known power density, qnd placing the other at
dny desired position, the power density at any position can be determined.
This is a "gross measurement" because the amplitude ripples can cause an
error ~s great as 2.0 db.
E. SELECTION OF TRANSMITTING HORN SECTIONS
As stated previously, the microwave facility was designed such
that a suitable quiet zone- minimum dimensions, 3' wide by 2' high by 1'
deep for two test samples side by side - would be uniformly illuminated;
a± 1.0 db power variation in the quiet zone was the design goal. The quiet
zone starts at a transmission length of 23.0' and is symmetric about the
chamber horizontal and vertical axis.
1. Design Frequency· Range
As discussed in Appendix A, the quiet zone dimensions set the
beamwidth characteristics of the transmitting horn; and a conical trans
mitting horn with uadd-on" sections was designed to give maximum gain with
the required beamwidth over the S-Band frequency-range. Under these condi-
ions, figure 11 shows the "design frequency range" for the appropriate
~ If: C ....
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sections (Dl through D6). This figure is a plot of power density (in mw/cm2)
per watt transmitted - Pd/W - versus frequency for each of the horn sections
at a transmission length of 23.0 feet. These curves are obtained by plotting
the expression:
p 1 r
X = A PT r
where GT is the measu.red
and R = 23.0 feet is the
GT Pd 4rr~
= w
gain of ea\,.h
transmission
as a function of frequency,
of the transmitting horn sections,
length. Thus pr A
r X
1 is the
, power density per watt transmitted when PT is the transmitted power.
It can be seen from figure 11 that, for the design frequency
a mtl1/ cma + lOo'o. ranges, Pd/W is 1.6 x 10- h For 250 watts of transmitted -watt -
lOwer - the recommended upper limit for continuous operation of the high
power TWT - the power density is 4.0 mw/cm2 ± 10%, which adequately meets
the design goal of 2 mw/cm2 in the quiet zone.
Neglecting reflections in the chamber, the power· density vari
ation for angles off boresight is dependent upon the transmitting horn sec
tion used (the gain), the frequency, ·the angle, and the transmission length.
The change in relative amplitude versus frequency for angles of 2, 4, and 6
degrees for each of the horn sections is shown in figures 14 and 15. The
change in relative amplitude is defined as the maximum relative power ampli
tude at a designated frequency (the gain at boresight), minus the relative
amplitude at the off boresight angle indicated, at the same frequency. The
curves were obtained from the measured an.tenna patterns. Thus, the curves
in figures 14 and 15 show the change in power density, for a fixed trans
mitted power and transmission length, at the angles indicated for each of
the horn sections. For the minimum quiet zone dimensions, starting at a
transmission length of 23', the maximum off boresight ang.le, in the H plane
(vertical polarization) is: l
tan 0 ~ 1.5 = ± 3.75 , and in theE plane 9E =+tan 23
., .;·).f''·i·J' ·· .. ·.r·a.t.t a
l 23
0 = + 2.5.
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It can be seen from figure 14 that in the design frequency range, the
maximum change in relative amplitude is 0.75 db, which occurs for horn
section Dl at frequency 4.0 GHz, (H plane, 4 degrees). Adding another
0.4 db due to the change in transmission length in the quiet zone (one
foot deep), the total change in relative amplitude, and hence the change
in power density for a fixed power transmitted,. is 1.15 db~± .6 db)
which is well within the+ 1.0 db goal set for the quiet zone.
For a qui.et zon~·4' wide X 3' high X 1' deep (9H';;: .±5°, eE'::. .± 4.0°),
the power density would be within+ 1.0 db (neglecting reflections). This
was borne out by the chamber evaluation discussed in Section III. ,
2. Horn Sections for Higher Power Densities
To increase the versatility of the facility, additional "add-on"
horn sections were designed to uniformly illuminate successively smaller
quiet zone volumes with increased gain. Thus, at the upper end of the fre.
·tency band (3.95 GHz) horn section DlO will illuminate uniformly ~.± .5 db)
quiet zone large enough for a single test sample- 1.5' wide x 1' high x 0
1' deep. This can be determined from figure 15 where for DlO and 9H= .± 2 ,
9 = + 1° ~A= .5 db. At this frequency, DlO gives the maximum p.ower den-E - , . sity obtainable for the system. From figure 11, for horn section DlO at
Pd/W _a
3.95 GHz, = 3.83 X 10 and the power required for a power density of
10 mw/cm2 is: 10
260 watts which is obtainable from the high to-2 = 3.83 X
power TWT in the system.
F.· DETERMINATION OF POWER DENSITY
As discussed in Section II D, the power density can be determined
by direct measurement using the standard gain horn monitor and figure 12, if
the monitor can be physically placed at the desired position. The on bore
sight power density can .also be det~pmined from the measured transmitted
power and figure 11. From the discussion in Section E above, it can be seen
that this value will be correct to better than + 1.0 db for any point in the
Quiet zone in the design ranges.
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QM-66-072 Page 9
In using the larger section to illuminate the 3' wide by
2' high by 1' deep quiet zone, the power density at any position can
be determined from the on boresight power density/watt transmitted
curve (figure 11), and the 6A curves given in figures 14 and 15.
As an example, for horn section DlO with 200 watts trans
. mitted at 3.95 GHz, the power density at boresight is Pd = Pd/W x a
power transmitted. Pd/W = 3.83 x 10- from figure 11, therefore, . l
Pd = 7.66 . 0
mw/cm2 • At the edge of the 3' quiet zone, 9H = ~ tan- 1.5/23 =
+ 3.75. Interpolating from figure 15 for DlO, a.H = .::!:: 3. 75; 6A is ap-
proximately - 2.25 db = 60% of the maximum amplitude, and the power ,
density is approximately 7.66 x 60% = 4.56 mw/cm2 at the quiet zone edge.
In a similar manner, the on bo.res igh t power density can be."
determined from the measured power density at any point in the quiet
zone. Actual values measured during a preliminary experiment are used
;s an example. The standard gain horn monitor was placed 2.5' off bore
sight in azimuth, and its meter reading was 2.4 dbm. From figure 12, at
3.2 GHz (the transmitted frequency) the frequency correction term is 2.2
db. Thus, the corrected meter reading is+ 2.4 dbm + 2.2 db = 4.6 dbm,
which (from figure 12) corresponds to a power density of 3.1 mw/cm2 at
the point of m~asurement. The monitor horn position gives a 9H = ± tan 0 0
2.5/23 = ~ 6~ 1 , and from figure 14 for ~H = 6 and horn section D6
(the horn section used) 6A = 1.9 db= 65%. Therefore, the on boresight
power density is 3.1 mw/cm2 x 6~% = 4.78 mw/cm2 • For this experiment,
the measured transmitted power (210 watts) gives an on boresight power
density of 4.72 mw/cm2. (from figure 11) which is in good agreement with
the above calculated value (4. 78 mw/ crrf) .:
III. EVALUATION: PROCEDURE AND RESULTS
1
The evaluation of the microlvave test facility was divided in three
phases: (1) the evaluation of the reflection from the walls and ceiling of t~e
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•.. ~
The Johns Hopl&ina Ul'li-'tity APPLIED I"~'UIC• I.AaOitATOIIY
~:· Sc:wing, MaryiMd
'!JESI IE I MRT-4-046 0.'1- 66-072 Page 10
empty microwave chamber as measured with an absorber backed dipole and
a standard gain horn, (2) the measurement of the reflections from a
single sample container (both occupied and unoccupied) in the quiet zone
and (3) th~ measurement of the power density in the chamber using the high
power source and the various horn secti.ons.
A. MICROWAVE CHAMBER EVALUATION
The·results of the evalua~ion of the microwave anechoic chamber
are summarized in Table I. It can be seen from this tabulation, that for
the required minimum quiet zone dimensions- 3' Wide x 2' High x 1 1 Deep.-, a total power variation of± 1.75 db is possible over the frequency band of
interest. At selected frequencies, adequate quiet zones with ~ 1.25 db
variations are possible. The measurements, performed with an absorber backed
dipole, indicate that .the power variations are primarily due to "amplitude
ripples" caused by reflections from the chamber walls. Maximum ripples as
great as± 1.0 db were observed. Figure 16 is a typical example of the
power variation due to reflections. This data is for a 25' transmission
length at F = 3.25 GHz.
The values obtained with a standard gain horn at 3.25 GHz (gain = 16.5 db) are also shown in Table I, (from figure 21) as an example of the
optimistic conclusions resulting from the use of a large area receiving
antenna. The horn integrates the reflected ripples over a !eceiving area
considerably larger than that Qf the dipole. Maximum ripples as observed
with the standard gain horn were less than+ 0.25 db.
The chamber was evaluqted by taking horizontal cuts, through the 4
foot cubic quiet zone which is centered equidistant between the side walls,
and the floor and ceiling; a distance 25.0' from the transmitting end wall.
The horizontal cuts extending + 2.0' from this quiet zone center, were taken
at elevation increments of± 1.0', ± 1.5', and± 2.0' for each transmission
length increment of± 1.0', ± 1.5', and~ 2.0' from the 25.0' center point.
These measurements were repeated at each of the six different frequencies in
the design range of each of the horn sections. Relative power as a function
f horizontal distance was recorded on an X-Y recorder, equipped with a roll
chart adapter, for each of the measurement increments.
'P :IQII • %
..... ~- .... ____ ·-· ... _ .. ' ....
TABLE I I'U<.T-4-U~o .t'age ll '1"'6 Jo"'"' Hopl.iftt Univenity
APP'LIED i"NYSICI LAIOIATORY
Sil..- Sp~i~. M¥-,1~ Quiet Zone Volumes and Power Variations • :we•
quer I Volume Dimensions for Power Variations of: Sect +l.Odb +1. 25db · ··+l.Sdb +1. 75db +2. Odb ~.::!:2. 25db - -
None None 2'Wx2'Hx3 1 D 4 1Wx3 1Hxl 'D 4 1Wx4' Hxl 'D 4 1Wx4 1 Hx4 1 D 6GHz 3 'Wx3 1 Hx3 1 D 4'Wx3'Hx2 1D (2.75db) D6)
4'Wx2'Hx3\'D
3 'Wx4'Hx2 'D
-2 1Wx3'Hxl 1D 4 1Wx3 1 Hx l' D 4 1Wx3 'Hx2 'D 4 1Wx3 1 Hx3 1 D 4'Wx4'Hx4'D
8GHz 3 'Wx2'Hx2'D 3 1Wx4 1 Hxl'D 3 1Wx4 1 Hx3\'D DS) 2'Wx3 'Hx_2 'D 3'Wx::i'Hx3~'D 3 1Wx3'Hx4'D
2 'Wx4'Hx\'D 2 'Wx4' Hx2 'D 2 'Wx4 'Hx4. 1D
3'Wx2'Hx%'D 4'Wx2 1Hxl 'D 4'Wx3 1 Rxl'D 4'Wx3'Hx2'D 4'Wx4'Hxl'D 4 1 Wx4 1 Hx4 1D , OGHZ 3'W'3'Hxl'D 3'Wx3 1 Hx2 1 D 3'Wx4'Hx3~'D 3'Wx4 1 Hx4'D (2.5db)
:n4) 3'Wx2'Hx3'D 3'Wx2'Hx4'D 3'Wx3'Hx4 1D
2'Wx4' Hx2'D
3 'Wx2'Hxl'D 4 'Wx2 1Hx2 'D 4 'Wx3'Hxl'D 4 1Wx4'Hxl'D 4 'Wx4' Hx2 'D 4 1Wx4'Hx4'D '
25G. 4'Wx2 1 Hx3 1 D 4 I v1x3 I Hx3 I D 4'Wx3 'Hx4 'D {2.25db)
:n3) 3'Wx2'Hx3~'D 4'Wx2'Hx4'D 3'Wx4'Hx3'D
3 1Wx3 'Hx4'D
.25GHz 4 1 Wx3 1 Hxl 1 D 4'Wx4 1 Hxl'D Great many 4 1Wx4'Hx4'D ,)
:n3) 3 1\<7x2 1 Hx2 4'Wx3 1 Hx3 1 D options
1rd Gain Many others )rn
None None 2 'Wx4'Hxl'D 3 1 \vx4'Hxl'D 4'Wx4'Hx2'D 4 1Wx4'Hx4'D
.45GHz 2'Wx2 1 Hx2 1 D 3 1 Wx2'Hx3~ 1 D 4'Wx2'Hx3 1D (2.25db)
(D2) 2 ~Wx4' Hx2 'D 3 'Wx3 1 Hx4 'D
2'Wx3'Hx4 1D
2'Wx2 'Hx%'D ·3 'Wx2 'Hx~ 1 D 4'Wx2'Hxl'D 4 1 Wx4'Hx%'D 4'Wx4'Hx4'D
.8GHz 2 'Wx3 'Hx2 'D 3'Wx2'Hx3'D 4 'Wx3' Hx4 'D (Dl) 2'Wx3 'Hx4 1 D
;
= Width H = Height D = Depth ::>tes·
.) All quiet zone volumes start at a transmission length of 23 feet and are symmetric about the chamber width and height center points.
(2) variations whose dimensions are ~minimum required values
Tbia doeumea\ coat&iu iAIOI"ft'la4ioa alfeeiilaa tbe na\ioa.al defeaa. of \be UD.ited St.aloee witbia ~be me.niac Df the Eapionap La ... Ti~le 11 li.S.C. ~ 791 ud TN. The~~« &be revelatioa ol ha C011t.eDta iD llD)' manoer to &D uft.llutbon.ed pel"'Ia ia prohibited by law.
Tht Jo),,, Hopltins Univenity IP,.LIE'O rHYIICI LAaO•·HOIIIY
• Silv ' '"J1a, ""-tyiWid
of missing "worst point'' cases, it is felt that the very large number of
data points measured represents a good statistical sampling, and the con
clusions summarized in Table I are represenoative of the chamber behavior.
B. EVALUATION OF TEST SAMPLE CONTAINER AND TEST SAMPLE IN THE CONTAINER
1. .Test Sample Container
Tests were conducted with a single test sample container in the
quiet zone. For the container havir~ no microwave absorbing liner, fairly
large amplitude ripples resulted (greater than± 5.0 db). With· the container
almost completely lined with a microwave absorber (the "radiation window" ex-, cepted), these variations are reduced to approximately~ 3.5 db. Removing
the plexiglass back that was on the container (the container is irradiated
from the back) and replacing it with a thin plexiglass back (1/16" thick)
further reduced these variations to approximately± 2.5 db. By absorber . 1 ining certain braces that are within the radiation window (and cannot be
emoved), the perturbations are reduced_ still further, to approximately
i 2.0 db, however, portions of the radiation window are blocked. In any
event, the test sample in the container perturbs the field in some different
manner and the question arises as to what constitutes a valid set of measure
ments: the sample and container immersed into an unperturbed field, or the
sample placed in an unperturbed field within the container (if this were
possible). In either case (the test ~ample and container, or the sample
alone), complex multiple reflections result.
Consideration should be given to the possibility of constructing
a suitably lossy microwave container with a radiation window of the desired
dimensions.
2. Evaluation Procedure
The evaluation of the test sample container in the microwave cham
ber was performed by mounting the container in the center of the four foot
cubic quiet zone (at a transmission length of 25.0 feet) on the horizontal
traversing mechanism. A monitor dipole was placed at a transmission iength
! 23.0' on the horizontal and vertica.l center point. Received power was re
corded as a function of the-horizontal traverse of ~he contain~r in the quiet.
The Jonru H~ina u,;..,.rtity .APP\.1[0 Plol'f'SIU t.A801UTOIIIY
Si!- S9tiNJ, ~~~ MRT-4-046 QM-66-072 Page 14
zone. The dipole was then moved toward the container in 3-inch increments
and the measurement repeated. This procedure was repeated for several dif
ferent elevations of the monitor dipole and several different frequencies.
The test sample container was moved behind the dipole monitor, rather than
the monitor being moved in front of the container, because, in the latter
case, the traversing mechanism would ''shadow" the container. Typical re
sults of the container evaluation are shown in figure 24.
To mount the container at the proper elevation level, the travers
ing mechanism was fitted with an absorber pedestal, upon which the container
was placed. The pedestal by itself (and the traversing mechanism) was evalu, ated as described above with negligible perturbations of the R. F. field re-
sulting.
3. Test Sample
The ··evaluation of a single test sample in the test sample cont;ainer
was performed in a manner identical to the procedure described above. Results
of these tests show that the sample in the container does· not greatly increase
the magnitude of the field perturbations over those observed for the container
alone - ±. 2.88 db versus.± 2.63 for the two cases respectively - however, the
phase of the reflections is changed such that where a maximum was obeerved
without the test sample, a minimum might now exist. Table II, below, is a
summary of the evaluation of the test sample and the test sample container.
TABLE II
Summary of Sample Container and Sample-in-Container Measurements Test Condition Field Variation
A. Sample Container Alone (Worst Case*)
B.
c.
Absorber Lined Container (3/8' ple;Kiglass back) + 3.63 db
" tt " (no back) + 4.88 db
" " tt ( 1/ 16" plexiglass back) + 2.63 db
Sample in Sample Container
Absorber Lined Container ( 1/ 16" plexiglass hack) + 2.88 db
Sample Alone** + .88 db
* Worst Case = greatest maximum to greatest minimum power variation in the quiet zone, for all positions of dipole monitor (see figure 24).
** Perturbations due to Sample movement alone, container and dipole monitor jiff-·
.IECREI. Thia doevD'!IIIta\ coataiu in.fotmMioa affee\iq tlM utloD.&I defeDall of tbe Uait.ed Stat.el withiD tbe mMDiD& of tbe bpioaap l.aW'I, Tit'S. 18 U.S.C,. ~ 711 aACI nt. Tbe t.raumiaioa 01' the revelatilm ol it.e coateota ia a.a7 mno.r to u uuu&bori.Md. pereoo;. probibiwo b7 Lt.•.
· TH• Johnt Hop&i,, Ur~i-aity APPLIED PHYSIC. LA&OaATOIIY
Sil-...r Sprii'I'IJ, !Mryl-cl
IIM!ft!i MRT-4-046 Qz-.1-66-072 Page 15
C. PO\.JER DENSITY
The final evaluation phase of the microwave test facility was
the measurement of the power density in the quiet zone, utilizing the com
plete microwave chain . . The power density was meas~red with the standard gain horn monitor
as outlined in Section II F, for various frequencies, and for values of trans
mitted power between 200 and 300 watts with the appropriate horn sections.
These measured values were compare~ with the power density calculated from
the measured transmitted power and the gain of the horn sections. The re
sults are summarized in Table III.
Freq.
(GHz)
2.6
2.7
2.7
2.8
2.9
2.9
3.0
3.1
3.2
3.3
3.4
3.6
3.6
3.7
3.8
3.9
3.95
4.0
, TABLE III
Measured versus Ca leu la ted Pmver Densities
Tx .• Horn
Section
D6
D6
D5
D5
D5
D4
D4
D4
D3
D3
D2
D2
Dl
Dl
Dl
Dl
Dl
D1
Tx. Hornl Measured Calc. Power Measured ~ = G . Tx. Power Density -mw/cm2 Power Density Calc.-aln I ....2 :a {Watts) (PTGT 4rrK-) mw/cm- Meas.
99.6
105.0
91.2
95.6
102.0
89.0
93.5
100.0
93.5
100-.0
91.2
102.0
89.0
95.6
100.0
105.0
110.0
112.0
228
226
220
216
210
236
234
232
226
232
232
236
245
260
278
250
250
250
3.40
3.55
3.0
3.09
3.20
3.14
3.27
3.47
3.16
3.47
3.17
3.61
3.27
3.71
4.16
3.93
4.12
4.19
3.70
3.90
3.0
3.2
2.9
2.85
.- , 3.1
3.35
3.0
3.45
3.0
3.6
3.6
3.6
4.15
4.0
4.35
4.25
-0.30
-0.35
0.00
-0.11
+0.30
+0.29
+0.17
+0.12
+0. 16
+0.02
+0.17
+0.01
-0.33
+0.11
+0.01
-0.07
-0.23
-0.06
NOTE:. For these measurements R = 24.0' (" ," · ... -·-~~
Thi• doeumeat eoataiaa ht!ormatioa all'eetiq tbe D&t.iob&l defe~ of the Un.it.ed St.aw withia the me&Aia,r of the EapiGa.aae IAW"', Title-IS V..S.C,. 8eet.ao. m &Del 1M. Til. tnt.camiaioa or the revel.a\ioo ol ita oo11teot.a ira aD)' maGDer to ao unau\bori.lled periOD il probibiw.d b-' Jaw.
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D. CONCLUSION
The microwave equipment at the Walter Reed facility is capable
of producing a power density of approximately 4.0 mw/cm2 in a quiet zone
adequate ;or two test samples side-by-side (3'W x 2'H x l'D) over the
S-band frequency range, with a transmitted power of 250 watts - the
recommen-ded upper limit for continuous operation of the high pow~red
traveling wave amplifier:
For reduced quiet zone volumes, a power density of 10 mw/cm2
is possible.
When evaluated with an absorber backed dipole, total power ,
variations of+ 1.75 db were observed in the 3'W x 2'H x l'D quiet zone
over the S-Band frequency range, primarily due to reflections from the
chamber walls <± 1.0 db). Using a standard gain horn as the field
probe reduces the observed "ripples" to less than + 0.25 db.
For a single test sample in an absorber lined test sample
container, field variations of + 2.63 db were measured. The movement
of the sample alone produced variation of + 0.88 db in the power
measured with the dipole antenna.
Fig. 1 MICROWAVE ANECHOIC CHAMBER
L·u".L- "+- V'+U
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MRT-4-046 QM-66-072 Page 22
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MRT-4-046 QM-66-072
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QM-66-072· Page 26
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TO MEASURE TRANSMITTED POWER: ADO CORRECTION TERM TO TWT MONITOR POWER METER READING.
Example: AT 2.7 GHz, THE CORRECTION TERM : .38 POWER METER READING : 2.00
CORRECTED METER READING 2.38 dbm:;. 140 Watts Pr
TO SET TRANSMITTED POWER: SUBTRACT CORRECTION TERM FROM CORRECTED METER READlNG WHICH CORRESPONDS
TO DESIRED POWER. AD.:UST POWER TO OBTAIN THIS VALUE ON TWT MONITOR POWER . METER.
CORRECTED METER READING Vs TRANSMITTED POWER +I
7 ~ ~
-I IE
~ ' -
-6
---- ----'"--- --· ·--
;Z -. -- ··-
~ ~
-::# ...
~ .
t & I I 1 1Jj _f l 1 .... .. .. ...
-
-- -- !-- ~- ---
-::::. ~
.~ ~
-,;;r. ~ ..
_LI.il
. ....
~ ~
L-# ~ -#~ ~
_I __ -- ...... -----£ ~ -~ I
i
-~ ~ ;z~ i - I
r2i ~ i-r- Example I
i i
I . I
I I
I
i I I I I I I I . I 1 I I I 1 • I l I • J II I I - ·- ..... ·- .,..,..
N
·fE c: u
T ffi 2.5• ao-2 .... .... :i Cl) z c:r a: .... ~ z.o .,o·Z 0."'0
.... !; :. ·a: ~ 1.5 110-z
> !::. (f)
z LIJ c a:: 1.1.1 ~ 1.0 110-2 0 ...
2
MRT-4-046 · QM-66-072
Page 27
Fig. II POWER DENSITY PER WATT TRANSMITTED FOR EACH HORN SECTION
(FOR TRANSMISSION LENGTH: 23.0')
l ...,.,
..-~ ~~ _, ,
~ ~ .JIIIII' ~ ..
,!"'\ ..-,. . ~ ..,-, .... · i
~ ,.•.c\0 ~ ,..
./ ,.
.... a "~ ;,;"" /i..- ./:' ~
, 7~ t'\C\ !_./ /~ ~
~ ,..
./ t7" / ./' / /" v / ,.. : / _,.. ~
~ ~ v 7 ..., ,/ ·:_/ v ... V / ~V /1 I ~ ~ v / '(\1 v / I _V
..-V ../.,. v /,.,. I .. /·I , ./"' v / ,.. . I v: ~·,
/ ~ / t)~V / / ~
./ ~ / ~ 7 _/ .../ ../ / ./"' ..-7 II'.. ~
""""' ,;""'" ; _/
./ ,.. v 71
""""' ,;""'" ~~
~ ~ v 7 ../
,. V"! I~ ""' . , / ../ \1~ , v ! '/' ...,
/ ../"' ./ ,..
~V _,'-/"' A :
A -~ ,.
~ .,
~"'J .... ~ ~ '/ I ..,. , I ../·,_ ~
,_ I__.,,~: . ...,.,~ ..,..'~' !
/ ,_,... ~
Ill"" ../
',ttl''ifl' 03 ..... , [ 2 -::;;;- """""""' . ! ~ """" l :""06. ~ "D.t .. ...,.. _,iii' 04- .../ I ,/ """""'" 01
. - f4- I
.../"" ~ ,.
~"""" ~~ I _, [7
> ....,.,-~ ...-~
'/" ,... _,-'r"'
... ~ ("\\ ~~
,- ...,,~
~ ,_.
! !
! I I I I I I
2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3
FR EOUENCY - GHz
5.0
....... ~ 4.0 ....... ~ ct: ~ 5.0
:t 0
2.0 -..... c., l&.l
~ 1.0 8
0
-r--f
FR[I ~UENC Y COJ RECTI
2 ~
? ~ ---· --- ---~ ~
.,.,..,- +-Exo rnp/1 ...-. ,.... Ill I 1 I l I I I I I I l II I I I I I 111 I IiI
ftfECliVE AREA-289 CMt:
-'JN CLJ RVE ~~
I
~
~~ v
~
I I I I a II I I I 1·1 I I I I II II I I I
·-
I I I I
TO MEASURE POWER DENSITY: ADD CORRECTtON TERM TO METER REA ..
EKomple: AT 3.0 GHz, CORRECTION TERM : 1 .. 4 db. METER READING = 3 .Odbm
CORRECTED METER READING : 4.4 dbm 4.4dbm * 3.0 Mllllwolts/ctn2
TO SET POWER DENSITY: SUBTRACT CORRECTION TERM FROM METER READI~ WHICH CORRESP.ONDS TO REQUIRED POWER DENSIT'
. ADJUST POWER TO OBTAIN THIS VALUE ON MONITO CHANNEL N2 I POWER METER.
2.1 • 2.1 21 2.t 3.0 3.1 3.2 3.5 3.4 s.a 3.6 3.1 s.a 3.9 4.0
-tiO
9
3
4
5
6
-
FREQUENCY {GHz) .
I CORRECT£ ) METER READh ~G Vs POWl RD r-Ns I
i I I
"7
: ~~ ~
I -··
~ ~----..;--- ---- ~---- !--- r-- - -- f-- ·- ·- -·-f-- ------r· ------ --- !---.;z~
I Exampl~f ./ ~
.# ~
i .;;a .£' I ~
l.:o~ p~ ~
;;iii ;;iZ ~ -I ~ ~ I ~
' ! -:~ ~
;" I i
i ~ ~ I
i ~ ..I
--~
. ~ 1 ll I 11 • • l I A I I 1 I I I I I Ill Ill II I
.25 .30 .55 .40 .50 .60 .10 .80 .90 1.0 1.5 2.0 Z.5 3.0 4.0
POWER DENSITY ( Milliwolls/ cm 1}
9 tJ' r IJ'
~',!! [:: r: TY
~~ ~ ~ ~
~..c g .;r
~ ~
'
--
OJ• OQ (I)
• N :I Ill 00
N
,.o &.o 1.0 &.o 9.0 ro.o
TOP OF''ECCOSORB" CV- C818(F) WALKWAY
SL~EVE . DIPOLE
3'611
r'-n!" 2
QUIET ZONE
MRT-4-046 QM-66-072 Page 29
---· t .T
---·-----------·]:__ QUIET ZONE LOWER LIMIT
5 SPLINE CABLE
"TYPE N" TO
1.
NOTE: COMPLETE UNIT IS WRAPPED WITH
''E:CCOSORB" AN 75
5 SPLINE CABLE TRANSITION
SUPPORT ROO
SUPPORT BASE
Fig. 13 FIXED DIPOLE MONITOR , STRAIGHT DIPOLE
·~ M.' stsr ('~ljN
~ 2 ......._~~ .... -::.-41'--,.___- +-~--+--.....;
~
0~--~--~--~--~--~--~--~ 2.6 '·
~ 2 -+---+---+----lr~~~--+-+---+---l "'':)
c:r c:r
4.0
H PLANE
--- E PLANE
QM-66-072 Page 30
J:)·:>::"2:>:;.:;j !lESIGN FAEO. RANGE
o 1-~-4---+-... _,~..,..F~~~-2 ~ 3.0 3.2 3.4 . 3:6 3:8 4.0
FREQUENCY-GHz
Fia. 14 CHANGE IN RELATIVE ANPLITUOF C/\41 FnR VdRintJ~ I=IYI='n
< <J.
.0 , -Cf ~
5~--+---r---~-4--~---+--~ , /
3
2
· QM-66-072 Page, ·31 ---H PLANE
---- E PLANE
6 -~-~;N sfcno~1 DJ~
/ I
I ~
~ ----rr---a..L ,-,- r v I' ~ :t60 /
5
~/ 1// / I I
v j
/ I 4
~
/~
3 _, .. ,..... ......
..., .. ~ /
.,.,. .,-""" ~ , v ("
~ :!:40 ~
,--' .,.. y I
/ 2
_.,. ~ ±20
_.
_ ........... ~-.fL~-: ~~-
0
3
~, 2 . ._ ..j,
l 1 .
o o~--+---+---~~~~--~--~ •·~~ 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 2.6
FREQUENCY· GH z
~ ..- ~~ ....,..., ~ MRT-4-046
I~ ~.1 111 •_ QM-66-072 .&J• r-1 ~d Paee 32
I T I I I I I T l I I -1 I . I I I I : I I i I ! I I : I ~~ : I I I I I I I I I I I
1 1 , , 1 1 1 .I ' ' 1 , ' 1 I 1 1 1 1 ... ' T 1 1 T r 1 ' , 1 1 • ! ,-
T 1 T 1 J : 1 1 ~~~ -~ _..r 1 1 : 1 1 1 1 ~' 1o. 1 "' 1 I I ! ! I
I I I ~---- I ~.... I ,; I I I I -v ! """"\'" f' "' I I ' i f I I I ,... I ; • I ~,.. I I I I I· "' 1'\; I i I I I l
t I I t1" t ! , i t 1.;1 • I I I I I f il' I I i i I .ill"; I I I I I I t 1- '~ I I ' I i I "' i IT i f'· i ,/1 I I I 1 1• ! · I I · I I I
I i I i i I ! i~.... ' I I 7, jl I I I
' 'I ! I : I I ' 1'1... 1 "" I I I I l ~ if\\ I I I
T "' r....: i I I ! ! l\ ! I I I .~ ':"' I i I I I I t
I I !"'> i I I ! i I II -I 1 I ! I I L.., ~ i I ~ I j I I j ! : I I ' ' :. I 1,1" I I I IiI f ~ A II' I·! I I i I i : I
I I' /I I ,. I I I I I I: ... , T ,,; !"'\;. -1 I I :
j I , , r ~ , ~ 1 1 _1 1 1 J , ~ 1 r~ ~ t t~ ; ' ' I j " ~ :# : I "' 1 .. I I I . ! I I u1 ., :...... I I I I I
I " i.o'"' 1 I I I "I I • • l • I lll I I I I I I i'\ I I.J' I I I . • I l ~ """ ~ I I I I
I i i' .....-; I ! I I !'( I I I I I T ! I Ll I L..oiil"' I I I " ! • I La I I I I I 1 I r T I I 1 I if • • I l.i .,.. ! ....._I I I I i I I -t I lo... i I I : ~ ,. I :ot I I I i : I
'J ;.... I i I '"""""'' l.o;o • .., II I tl I . "" IV i I ; I ~ io-'1' I r-1... ...:,.. ....... '... I . j,. I I : ' •' I ' I 1\. I I
l ! IJ I ! I I j,.oo' I I : f I I -TI : ~1 I J : I ! T I
. ~ T I I I { I i ~ , •• I ' I ! ' ', !". 1 I l I 1 I
! ' I " I I U' "! i I I ~ I I I I I I . ~ ~ 1 "" ! I I 1\ I '~ I I I I I !'- ! i l I I I :.."' I ' I
l I I I ~ I , ! . I ' I ~ ! I I I I l i'"\1 I 'li
I / I I i 1..., I.. I I ~ • ~ I # : I I I ' I T I i ' I I ~ L..., :"( ......... T --.;..,: : I ~ - '..,!/ i I ! • ' i I I I 1 ; I l.t AI I l... it' ...('!
~:-...::~, ... ,~,..;_.j.....<IH-+-+--t-H-+-+++*-,.r-+,-+ ~. I i i I l • ' I l I I 1 i I :.:-.. !.. ;..... r.:: j I I I ,... '"'-' I I """"' : • I 1 I I I i I ~ "~ ~"' I' .:"\j I I
I ; 1 IJ root.., o...· , 1 ,,, I I I~ 1 - I I 1 • i I • '-1 1.:.., I V
I ! I ; T . '"!"'- ..._.,. : I I I • 1 I I i I I i "' :.... ~ ;.,;: ~ I : I 1 i ' I I I., .. ~, I I T I T 1 ' T T ' I L : .... "
I I · I I : t I ! I ' I I I I ! I I I
! ' ~~ j i.,.. I j
r T , ' I I" i I I .T !\.... I I I ! : ; I ! I I I ~ I I I ... I I T I 1 I I I r T i I .... I I 1 !
: I , I il~' ; I I a I"C I ! I I T r I I v I I : I IT I ·~ ., I· I I I I I ~ It I l ; I l I ~. 1\~ I i I I I I 1.1"' I 1""'1" I I I l I I I I l i i! .-- .... I~~ J...~. I 1 ' ·! I I I l I I I I 1 I ~ 1 .... 1 I;. I ! r I I 1 I -.,; I 1 I ·: ! : I : I I I ' :"""' I I I ' ITT I t t i I I'" . "' I : I I !
i !' .... ! I l I I . l 1 ·~!I I I I I I ; I I ! I I ! I I I r I 11 ! I ! t '1 '1 . I ; l l ,.,. I lla ~ I I ' I i I I !~ Ill I f I I
I "' i I I i J J l II I ! 1 ! I
I l . ! J I I I · I I · l f I I I I
: T I I io"', 1.... •• I I I ., I I I I I I I I I
I • l I : :, I l.oorl ·~ : I ! ; I • -. I I 1 ! ; I I i i ; .f I I !\.. " : i l I ! ! I I i I I I I ' i · -r ~ , '· ! ! 1 • 1 1 ' , i 1.
I l l t l1 I I I' • ! I I I I . I I I !II.. II"' l f .. .._ I I I I i I I
r • , i""looa "'- 1 •J 1 ! 1 1 , 1 i ' I ! ~""' I r"'l~ ,. I ! 1 I I I I f t I ,...,.... ~ I '.J ; -T 1 I
()
0
,...--.-'IUNS HIBIIOH LIHCTH • 23.01
AL uu.nvs PCIIII UViL (db)
IN HOIJZ OHTAL DIITANCII or KU. Cl
;tl.O' tl.S' _:tl.O atfrtl
HAl :::~LO::: : ~:t:il:::: :~:t;n .... ~ +1.0 2.0'
KIN : ::~t:s: :: :~j;2s::: =~:k7 r··· -l.O
KU ~ ::;: ~/. l'h //- ~ '/,; /~ +l.O t.s• '/ ,,_, ~ :;I' ~ :1.~ 'l. ~ ~ 0 KlH '/ z ,, -0.75
KU . ,., . +0.5 1.01
KIN -o.s HAl ~
')(
+O.S . t o.o
KlJ -0.5
KU '· +O.S 1.0' KIN -O.S
.J.s• KA.I ~ /1./h 0~1"~/ "l./: +0.5
KIN ~&Y'~ ~o@?-~~ t¥~ -0.5 ..... ~ ~ .... ···*····· ~ ...... ·····
KU ::.:o:.:u::. :;.;0~25::: 2.0'
:;.;Q~l s:::. +O.S
MIN ::.;1:.:25::: : ;..:1~2~::: . ;.;1:2 s:::. -0.0
TRAHBtCSSION UUfCTH -26.t'
:AL IlLATIVE POII!R UVIL (db)
lN HORIZONTAL DISTANC!I or: HAl. tiC I
!2.0 1 ;!l.S' ±1.0' RIPPL2
HAX -2.25 -2.25 +0. 75 2.0'
KIN -4.25 -4.25 -l.OD
f ~ IWi MAX +0.5 1.5'
"HIH .
~~ lUi -1 5
KU I /: I i-Q. 75 l!O' KIN '/
-0.25
HAl .'// z r/ /,-/ +O.S 1/
R 0.0 ~ ~f': '/ '//. I' 0 KIH I / -0.75
II I 0 v,~ '// l.O' MAX '/. +1.0
/I / I' -0.5 KIN
l.S' .MAX II ~ +l.O
KIN II ~ -0.75
2.0' HAl -0.25 -0.25 +O.S
HIM -t.n -t. 75 -D.S
'I'IJJIBMllllON UHCtH • U.S'
uunva fOlia UVIL (db) lH HOUlOlf'UL DlltPCIS Of
~ ~~ ~ ~~~~~ ~ ~~~09~
v~~~ '.1£
~rr. ~ 1.~~~ '
Rltrt.l
+0.7S
-0.75
+O.S
-0.5
+O.S
-0.5
+0.5
-0.5
+0.5
+0.5
-0. 7'i
+0.5
-0.5
TIAHBK188IOH URC111 . 26.5'
uunva PCIIIR LIVIL (db) IN HOIIlONTAL DlltABCII or, HAl.
±2.0' ±1.5 1 !1.0'. lllrtl
-2.5 -2.5 -2.5 +1.0
-4.75 -4.75 -4.5 -1.0
II ~U lUI II ~ . ~ ....... ::;.::l;o:::: ::.:.~.:o:::: +0.75
III.UIHIII : ::::~;s:: :: : :.:.::J.:2s::: -l. 00
: ~ ~~~ i o::: ............ .. . . . . . . ~ .. :: ;,=1; 0:::: ; =~:z:.:g: ::: +0.5
::~:j:~::: :::~;5:::: ::~J;s:::: -0 75 ::;.:q:s::: ::~o;~:::; : :~&L5:;;: +l.O ............ :::2:25:: ::.i;is:: :::..::z:zs:: -0.75 ••• 4 ~ ••••••
::~n;;:::: ::~o:s:::: +O.S :: ;.:o~s::: ... ······· ::~2:2:;:: ::~:.::75:: :: ;..::z~z':: -0.5
!IIH~.IUII :::o:13:: ::~o:rs:: +0.75
•tH~I.I~tll ::~2;23:: ::~i:is:: -0.7S
-o.s -D.S -0.5 +0. 75
-2.0 -2.0 -2.0 -0.75
tUHIHI881011 LIHCTH • 24.01
UUTIVI I'OII!R LIVIl. (db) IN ltOIIlON1AL DtSUMCII 01 KU.
+2.0' !l.S' _:tl.O' Untl
'/frt'~ ~~0~~ +l.O
~ ~0::~ ~~~ 0(0: -0.75
1'/T-~'0~4~0 ~~ +0.5
0 ~(0/~" ~~ %~ -0.5
~ .~ ~~0 0 (.// 7h1'~ 'l/. '/ j!/ '/ //}"/ 'l ~ ~
+0.15
-0.5
+O.S
-0.5
+0.5
~;;% iZ -0.75
~V.:i% (.1~~~0 +0.5
~~ ~~~~~·-o.s ~~ %o/~ ~~ ~ ~ +0.5
@a'/~~ /1~~~ -o.s
TUHSKI&SIOH UNC1B • 21. O'
uunvs r011a uvu (en~) IN HOillONTAL DlltANCII or lUI.
:!:2.0' :!:l.S' ;!1.0' IIPPLI
-l.O -l.O -l.O +0. 75
-4.5 -4.~ -4.5 -0.75
I +0.75
I -0.50
I +o.75
-0.75
+0.75
-0.75
+0. 7S
-0.75
<tO. 75
-1.0
-0.75 -0.75 -0.75 +0:0
-2.25 -2.25 -2.25 -0.0 .J
TUIIIMIUIOH LIIICTH • · 25 .0'
UUTIVI ,...,.. LIVIIL (cllt) II HOlllONtAL DliTARCII OP.
:!:'·'' +1.0'
HNtmll .: ;.:1:1'::. :~LJS: :: .....................
IHHtHII : : ;..:} : s : : .. :; l ~ 5: : : :
- ::-;r.:r::::~AZt~r~ ·~ ::;,L;~·::: ::;.oj~L:::io.~;s:::
Figure t 7 CliAHBER "EVALUATION
HAl.
llfnl
+l.O
-1.0
+0.5
. -0. s +0.5
- 1. 25
+0.75
-0.75
+0.5
-0.75
+0. 75
-0.50
+0.5
-1.0
FREQUENCY: ____ z_._6 _cH_z ________ __
TRANSMITTING HORN SECTION :_o6 __
RECEIVING ANTENNA: Absorbt-r
backed dipole
OATE: ______ s~-2~2-·6_6 ____________ _
NOTES:
;:::::·:·:·:·:·:-:-:·:·:·:·: • +0. 5 t 0 - 1 . s •. .! l . Od b
• +0.5 to -2.0 • !l.25db
~~~ • +0 .. 5 to -2.5 • _!I. Sdb
• +0.5 to -3_.0 • !I. 75db ~---.. • +0.5 to .).5.• !2.0db JliM!iMWflil
• +0.5 to -4.0 • !2~2Sdb ,_..illiiiii;WC
• +0.5 to -5.0 • !~.75d~ ..._ _ __..
CAL
lfCI
J.o•
t.s•.
t.o•
l o.o
1.0'
.t.s•
2.0'
ICI
l o.o
t.o•
l.S'
z.o•
HIM
MAl
HIM
MAl
KIN
HAl
KIN
HAl
KIN
HAl
HIH
HU
KIN
TIANI~IIIOI LINCTH • IJ.O'
ULlTIVI POIIEI UYIL (ctb) lR HOIIIONTAL DlltlHCII OP M&l.
~2.o• tt.s• • :t.o IJPPLI
::::i~l:::~:::::::;: -2.75 v'\.'V\.'l.ILI(.>t -0.25
···o·o .... -H» s : :-: . ~ .. = :; ~. .
::.:1~3::::: -0.5 ....... ~ .. "
:~:.,;~::::: +0.5
:;.:1~(!::::: -0.5
::.:oic:;::::: -H».5 . ~ . ' . . . . . . . . .:c;u::::: -o.s
. ,... ::.:o;~::::: +O.s
:::.::~t::·::s:::::::::: -1. 5
::::::::::!:;:)::::::::: -2. 75
::.:ti!)::::· -0.5
::.;o;5::::: +o.s ::.:1;~::::: -0.25
-H».S -0.5
TUNStCSSICII UNC111 • 26. t• IILATIVI POWIR LIVIL (db) H llOiiZOHTAL DJSTANC!I orr KAI,
•z.o• ~l.S' .:!;1.0'. RJPPU .
KIN . :-:·:•a:·:D:·:·:·:·: -2. 2S • 2. 0 -0. 75
TIAMiimlllOM LINGTH • 2l.S'
ULATIVI.I'CIIIR UVIL (clb) Ill HOUI.OilUL DIIUICII OF
~ -1.5
=:~u;:~,:
::;.:t;7j: ::.:.o;o:::
: :.:t:;s:::
::.:.o.:o:::
::.:t:;n::
::.;t:;o:::
:::.;z:.:o:::
: :.;o:.:s:::
:::.;1:.:]5::
-~ ~ -2.5 r'll'll'~
lUI.
RIP.U
+0.75 -0.5
+O.S -
-0.5
+O.S
-0.5
+O.S
-0.25
+0.5
-0.5
+O.zs·
-0.25
+0.5 -0.5
TllAN8Kli8Ulll UNCTH • 26. S'
R!LATIVI fCIIII tiVIL (clb) IN HORIZONTAL DIIUJICII ora HAl.
~ ~ ~ - l. 7 5 • 1. 7 5 +0. 2 5
~?.: ~ -2.75 -2.50 -0.25.
~~~~ ~ -1.25 -1.25 -t-0.5
~ ~ ~ -2.5 ·2.0 -0.5
~ ~ ~ -1.25 ·-1.25 +0.75
~ ·(:{ ~ -2.75 -2.75 -0.75
% ~ ~ -1. 75 -I. 75 +0 5
v. ::j ~ -1.0 -1.0 -0.25
:.; ~~ -1.5 -I. s +0. 75
/.)(t;~ -1.0 -2.5 -0.75
-·
IIAHINJ8110w LIIGTH • 14.0'
IIUTIVI fCIID LIVIL (4b) 111 HORIION'bJ.. DUtliCII 01 ti.U.
IJtfLI
-l.2S ... 25. +0.5 -3.0 -2.25 -o.s
::~o;s:::: :..:a.:1::::: +O.ls .... ~ ~ . . .. .. . ~ ........ . ::;.:t;s:::: :.a:.:o::::. -0.25
. . . . . . . . . . . . .... ~ .... ::;.:t;s:::: :..;t:.:ls:::: -0.5 ....................... .:o.o;s:::: :..:o:.:s:::::: +0.5 ...................... ·::.2;a::: :.;a:.:s:::::: -t.s
........................... ::i-2;0:::: :;2:.:0:::::: -0.5
·::.· -1.5 -l.S +0.5
-2.75 -0.75
TllANSH1881DII LI'NCTI • 2J .0'
ULATIVI PCIIII UVIL (4b) 1M HOIIIOHTAL Dll~ll OP HAl.
!2.0' t1.5' !1.0' RIPPLI
w~~~=~2Us<;( -H».25
8"(~ ~~ ~~~~~~\~i~( -0. 25
:::~:t:·:::rs:::::::: ::::~::f::;i:::::: :;;::i:~:;:s:::::::::::: +0 . s :::::~j~:~J»::::::: :~z;~::7i::::::::;: -0.5
\1:{2:;:::::::: ::\:I:/23::/:- -+{). 75
:::~i4t::::: \::::~::::~~):::::::: ::::1~:~.\g:::::::: -0.75
:::~:t)i::::::::::: :::::~::t:~:~:::::::::~: :~~r~::t.::::::::::::::: +0. s .~ .............. . :::~:l~::s::::::::::: :::~~~::s::::::::::: :~!~:s::::::::::::::: -o. s :::;::t;::~::::::::::: .:::~:j~:~::::::::::: ~:i:::(;::::::::::::::: +0. ~
\3~::5::::::::::: :::*:~~:25:::::::: :~3~25::::::::{ -0. s ;:~::t:::~::::::::::: :;:t::.::::i:::::;:;:;: ~::1:::j:::;:;:;:::::;: +1. 0
:::~3~::£::::::::::: ::::~:3~:<r:::::::::: :~~~:~~::::::::::: - '· o ~~ W"~ :~:j:~:2f:::::::: +0. 5
~~ Vff/}f0 :)}:;:~i:;:~:~:~t~: -0. S
TIAJIMIIIlOM LIHCTH • 2'.0'
ULlTIVI I'CJift UVIL (db) t• BOIIZONTAL DIITANCII 0~ ~·
!2.o• ,!t.s• !l.O' um.a :::::~:L:i//::: <::~:i~:~:::::::::: - t. s +0. 5
.:::::::}:::~:;:;:;:;:: ::::~:~:~:~:::~::: - 2 . s -0. s -1.0 -1.0
-1.0 -1.0
-0.5 r~x-_.' +O.S
-2.!5 .t<-Y ~: .,.il1 v ~--0.75 +O.n -2.25 • .... =:>.'~~-~. r .. <.-: -0.75
-l.S
-1.0
-l.O
-1.0 -2.25 -0. ')
+0 ) ::::~i~::):~:::::::: ::: -1 75
Figure 18_ CIIAMBER EVALUATION
-0.5
FREQUENCY: ___ 2_.s __ cH_z ________ __
TRANSMITTING HORN SECTION: ns RECEIVING ANTENr~A: Absorber
backed dipole
DAT£; _____ s_t_2_JI_66 __________________ __
NOTES:
;
• 0 0 • 2.0 db •! l.O db
• 0: 0 - 2. S db • ! l. 2S db
• 0.0- l.O db • + l.S db
•O.O-J.5db•;! 1.15db
• 0.0- 4.0 db.! 2.0 db
I CAL
lHCJ
2.0'
1.-S'.
t.o•
m o.p
t.o•
J..S'
2.0'
£CAL
lHCI
2.0'
t.s•
1.0'
!R 0.0
1.0'
t.s•
2.0'
MAX
KUI
HAl
TIAH8HIS810H LIHCTH ~ Jl.O'
ULlnVI PalER UV!L (clb) IN HORIZONTAL DIITANC!S Of HAl.
~~~ ~:'i. c-.~ ~ ~) '.% ~' ~~'%
RlfPLI
+O.S
-o • .s
HIN v ~~~~~ HA.I ~ '"' ~ =~~~~~?~~ =~~~~l~~~iii~~ +0.5
Hl.N
MAX
MlN
HA.I
KIN
·MAX
MIN
TRANI!'ISSIOH UNC'nt • ~6 ...
IBLATIVI PalER LIVIL (db) 'H HORIZONTAL DlSTANC!8 or: MAl.
~2.0' ~1.5' :!;1.0' RIPPLR
+0.75
-0.5
+0.25
-0.25
+0.25
-0.25
TIJ.NSHIIIIOH LINCTB • U.S'
RBLATlYE fCIIBR LIVIL (db) · IN HO&IZOHTAL DIBTANCII Of MAJ.
:!;2.0 1
::~4~~::.w
+1.0' RlfPU -=--at---... +0.5
x ·~ '-"-"' ~~~ .... :-....,, ... .._.,"-,". -0.5
+0.5
>< ~:~' :~~ "'
~~ ~ }~~~~li:~: {~~~1)\i t'-' ~-- ~ .~ ~I'll
:: :•t:.;JS.::
+0.2S
-0.25
+0.5
-o.s +0.2S
-0.25
T0.75
-o.s +0.5·
-o.s
TRAH8ftl8SIOH LIHC'nt • 26.5 1
RELAnVI PCJIIR LIVIL (db) IN HORIZONTAL DliUHCU orr KAX.
:!;2.0 1 :!:1.5' !1,01 RlfPLI
Ill~~ I ~llln~~u;,.x. L~~w.. +0. s --III~HlNIII ~x·· . .....-~:ID.: -o.5 :::-::z~~-:: ::~~;~::: ::~~~~:::: +0,75 ::~4~z5:· ::~4~25:: ::~li~2s< -1.0
[• (; ~<..r_,.
+0.5
\~ K) -O.S
~ )'. ~; ~ +0.25 :,;:-; " -0.5
~- +0.25
!X -0.5
:i~z:~~:.::: :;.;~:-~:::: ::.:~~:Q;:: ;.o.s ::~:.:~:is:;: ~~:s.:o~:~: :~1:.~::: .o.s f1Hl~I11Jl ·~~ ~x.~.J'Il'.v. +0.5
HlUU~III ,..v,.-.. ,...v .o. s
TUHSKI8810H UIIGT11 • 24.0'
ULATIVI I<IIBI LEVEL (db) IN HOII!ONTAL DIBT.A.NC!I 01 tid.
:!;2.0' +1.5 1 +1.0'
~"~ ~--.,:;.:: ~ '~~ : : :~ J:-]9: : ~ ~ ":~
llffLI +0.5
-0.5
+O.S
-0.25
+0.25
-0.2S
+0.5
.. o. 1s
+0.5
-0.5
T0.25
-0.25
T0.5
-o.s
1'1Alf8Kl881CRI LIHCTB • 27 .o• ULAn VI IOWD UVIL (db)
lN HORlZORTAL DlBZANCII Of MAl.
ltrPLI
-2.75 :.;.2~ 1S:: . :~2:~?!i::: +1.0
-s.o :~4~o::~: ::~,.~~:::: -1.2~ :::-:~~~E:v ~J '~/.~ ~ +0.25
:: ~~~': J~ -){_ '/~~ ?0. -0.5
~~~\ • r.l'. ~ +O.S
~~~ ~ :~ >-: :r .o.s W'~ 'l. ~, ~\ ;.o.s ~ ~ '0 1>.. ~ .. o.s ~~· ~ '/It", +O.S
~ ~ /.~ -o.s :::-:~·J:::~ ~~~ ~ ~~~ +0.5
: :;.:3·~: .. ('l ,;, ~-~ ~J~ .o.s -1.75- :~1:~75;: ::~r..:n::: +O.s
'IUJ(JHJastOll u~~:m • n.o• ULATIVI rowD UVIL (db)
II HORIZONTAL DIITANCII 0~ MAJ.
+2.0' · +I.s• :tt.o•
!l ~ Ill~ II ~ Ill~ ~:?: -~ 1.!' r:?~
~' 0~· • ·X
~"~~~ :;<. v: ·>. • ~ ~ :1.~ .'-\. •• ·,r~ -<,
anna · +O.S
-0.5
+0.5
-0.25
+O.S
.o.s ;.o.s -0.5
+O.S
-0.5
+0.75
-o.so +0.5
-0.5
Figure 19 CHAMBER EVALUATION
. FREQUENCY: __ 3 ·_o_c_.n_E -----
TRANSMITTING HORN SECTIQN:._0_4 _
RECEIVING ANTENNA: Abgorber
backed dtpole
DAT[: _____ a~/2_2_16_6 ____________ _
NOTES:
'I CAL
~HCI
HAl a.o•
KlH
1.s•. . MAl
KIN IIAI .,,.,. KIN HAl
D 0.0 KIM
HAl 1.0' KIN
.l.s• HAl
KIN
J.o• HAl
HIM
I CAL
A.NCI
HAl .. 2.0' HIM
HA.I l.S'
KIN
HAl l.O' HIH
MAX II 0.0
KIM
1.0' HAl
··, -HIM
t.s• MAl
HIN . ·· a.o• HU .....
HUt. i .
ti.AN8KISIIOR U~ • U.O'
ULAnVI fOIEi UVIL (clb) IH HORIZONTAL DJITAHCII Of MAJ.
,:t2.0' tl.S' ;:!1.0
r/.1. '/ ~ • 'jl .t.JV<:J-.
~~~[\ ~~-,~--~
I"-"".,~~ ~~~~~t:$.Hj~ )~l~;~~j:~:~~ ,, -'-' :'>..'- ....... ~\
z '/. '//.
llffLI
+0.1)
.. o. 75
+O.S -O.S
+O.S
-0.5
+0.5
-0.25
+O.S
-0.75
+0.5
-o.s +0.25 -0.50
TRANIHIISION LIHGTH • 26.11
... IILATIVI POU!R LBVIL (db) ~M HORIZONtAL,DISTAMC!8 OF: HAl.
!2.0' .::!:1.5' ±1.0' RIPI'U
-2.75 :~LiS::: ::.:Li;::;: +0. 75
-4.5 :..:4~=5:::: ::.:It ~=5::::: -0.15 .... ~ .. ~ .... V/. r/. '/ '/ '17/ +0.5
~ '/ ~[I ~ -0. s •/,
~ ·, +O.s
I' ~ -0 'i
+0.5
-0.5
+0.5
:') " ~~- -o.'s I; '//
r.;: '/ '/ +0.5-
~ VA :/ '/
':I' '/ '/'. //,WVK//.1. -o.,. . . ~ .... " .. , .........
-2.75 :.:z~n::: ::.:2irs:::: +0.5 .,, 5 .1'11111 :.=4;:z:s::: : ~' ;~:~ ~:: -1.0
~ ~~. ~~ Zf:.c;-·~11 Dr..~ ~ .. t L.fl,...~ ~
TUNSHtSIIOH LINCTH • U.S'
UIATIYI fOlia LIVIL (clb) JH BOIIZONtAL DI8tAHCI' Of MAl.
IIPPLB
+0.5
-O.S
+0.5
-0.5
+0.5
-0.5
+.25
-.s +0.25
-0.25
+O.S
-0.5
+0.15
-.5
TBANSMISSIOM LIHCTH • 26.5'
RIIAnYB PCJIIR LIYIL (db) IH HORIZONTAL DllliNCII Of1 MAl.
:t2.0' ±l.S' :!;1.0' llfPLI
-2.5 -2.5 -2.5 +0.75 -0.5
+0. 75
-o.5o +0.5
.0,5
+0.75
ljj jl ~~
V/ I{ -0.75
f?'/. ~~ '//I'
::~~:.:u:: '/ rl) 7 /
+0, 75
-0.75
+0. 75
-0.75
-2.75 -2.75 -2.75 +O.S
-4.75 -4.75 -4.0 -0.5
TUIIIH18110H UIICTII • 24.0 1
UL.ATIYI r<llll. LIYIL (clb) Ill HOIIIONUL DIITAJICII oil MAJ.
!2 .0' +l.S' ;tl.O'
~ ~ ;;:~ z '/. ~ z
R · i ~~~~~;.-~0<
llrrtl
+0.75
-0.75
+0.1S
-1.00
+0.5
-0.5
+0.5
-0.25
+0.5
-0.5
+0.5
-0.5
+0.5
TIWC8HI88101 LIHC'IH • 27.0'
IILlTIVI POWER LIYIL (db) IN HOIIIOHTAL DIItANCII OF HAl.
,:t2.0' .::tt.S' :!;1.0' llPPLI
-2.0 -2.0 -2.25 +0.5
-1.25 -).0 -J.O -0.5
:;~i~~:::~ ~ ~ t/0 ~ /",0 +0.75 : ::.:]:.:s: ;:~ ~
//_ V/ '/ ~ -0.75 "L· "/:.
~ u. z v z 'l/.l% ~ ~ +0.75 "r :// ~ ~~ :;(;: ~I'/ r/ 0 -0.75
t% Y. 0~ z ~ +0.5 '~.
rl.~:~ ~[I :; :/~ Cl .;;; -0.5 '/ '/
~~ v '/ :1' ~ +0.5
~ ~ ~[/ .'/ z ~ -0.5 ;-', ............
~//~ ~ ~ :: :.:2~:,s:: +0.75
:: =~4~2;:: ~ ~ ... /. r-y ~ -0.50
-2.75 -2.75 -2.75 +0.75
-5.0 . -4.5 -4.0 ~· -0.75
11AUM11110N 1..111:111 • 15.0.
ULATJVI fOIID UVIL (db) 11 BOllZOWTAL DIIT.ANCII OP. MAl.
+2.0' +1.S' +t.O' llft'U ...... ~ ... "' .. . ~ ... ~ .... ::r-2;1~:: ·::;.:J:Q:: ::-o:t.:O:::· +0.1S :::.1i;n:. ::::.4;:z:s: ::~l.:.:q.:::· -o.1s ~~~~0 vf0;~ ~ +0.1s
~~~~ ~ ~~~~?:% -0.75
~ ~~.~ \ ~fS'' ~ +0.5
~ s ~~~\ ~,~.:'\.' ~ -0.5
~ \ ~~~~ ~~ ~~ +0.5
~ ~~"" ~ ~ -0.5
~ ~ .~ ~ ),'-~ ~ ~ +0.5
~ ~ ~~ \: ... '~ -0.5
~ ~~~~0~ 0 ~ +0.5
0 ~ )Z~/:~ ~ ~ ~ v; -0.75
:=~~:.:s:::: :::~:~~L: :~r.:~:::: +.2s ... ::.;.J;s::: :::;.J;s::: ::..:)~:s::: -.25
Figure 20
CHAMBER EVALUATION
FREQUENCY: ____ ~l-~2s~cn_z ______ ___
TRANSMITTING HORN SECTION:__::.o.;;...l _
RECEIVING ANTENNA: Abaol'ber
backed d t pole
• OATE; ______ ~s/~2~2~16~6--~at~z~l~/6~6 ____ _
NOTES:
•
• 0 s - z. 5 • ! l. 0 db
. . o: 5 - ). 0 • ! l. 2S db
•0.5- ).5•!;1.5db
~. 0.5 • 4.0. +' '· 75 db
~: ::: : ::: : ~ :::~: .
CAL
N~
HAl 2.0 1
HlN HAl t.s•· . KIN
MAl · l.O'
HlN
HAl • o.o KIN
MAX 1.01
KIN .. MAl
.J.S' KIN
2.0' K.\1
KIN
CAL .NCI
MAX 2.0 1
MIN
K.\1 1.5'
KIN
1.0' KAX
taN KA.I.
:a o.o MIN
1.0' HAl
KIN
~·'' MAX
MIN
2.0.~., MAX
liiN
TIANSHISIION LINGTH • 2J.O'
UU.TIVI PCIID LIYIL (db) lH HORIZONtAL DIBTANC!S OF MAl.
;:::::;:::{:~:¥~:::: :::::::~:t~:j~:::::: :::::~:2::::s:::::::::: ::::::~~~:s::::::::- :=::::::;;2:i:ft::::: . :;::::~~:~~::::::::: :;::::~:t:~~:;:::::. :::::::~:!:~&:::::::::
:::::::;:K~i::::: :::::::~:t:::s::::::::::
llflU
TRANS"'SSIOH L!NCTH • 26.81
~RILATIVI PMR LIVIL (clb) ~N HO~IZONTAL DIStANCES OF: MAJ. , ~2.0' :!;l.S' :!;1.0' RIPPLI.
. 1/.~ ~t%~~ 0W#M " 1l~=~~~:~~(
~:;:~:i ;:~(1~:~;
~~1~f~~1( .. :::;;:t;;:~ol::
~H~~i~i~i.~~~~ ~H~i~H
+.l2S
-.us
+; l2S
•. us
TRAHSHIBiiOit UNGTI • U.S'
ULATIVI fOIIII UVIL (clb) IH HOUZOHtAL DIBTAMCII OF MAX.
:!;2.0' +1.5' :!;1.0' RIPPI.E
r.t'VVV'.IV<.X ::::::~t.+:~~:::::: ::::::~~;:~s::::: :;:;::;;:jl:S::::::::: ·::::::~~~:5ii:>
:::::::~fl::i:::::::;: ::::::~{t:;:i;;:::::: ::::::~~:;:);:;:::::. +0. l2S
:;::;::~i~:j~;::::: ::::\:t::~:s:::::::::: ::::::~:t~if::::: -o. 12 s ·::::::~:Q:~:if::;: ::::::~;P.:~:Ji:::: ;:;:;:~~:~i~::;:: +.l2S
::::::::;:i:::2:S:::::: :::::::~H:1i::::: ::::\:t:~i~::::: -. 12 s . ::::::~:1:~:5:::::::::: :::::::.:::f~:J:::::::::: ::::::~:);:~:~:::::::::
. . .................. . ;:;:;:;~:i:~:(j:::::::::: :::::::~:i;:u.::::::::
• TRANSHIISJOH LIHGTH • 26.5'
RELATlVI PCJI!R,J.BVIL (db) IN HORIZONtAL DlltANCI8 OPt MAJ.
±2.0' ±'·'' ±l.O' IIPPL!
..
TUMSHJIIICII LI1IGTH • 24.01
ULATIVI taml UVIL (db) lH HORIZONtAL DUTANC!I 01 HAl.
:::::::~::~:~:((::::: ::::::::~:ht.:::::: :::::~:;~:~:~f?\ :::\~~:~:~:::::::: :::::::::~:2:~:\f::::
UPft.l
:::::::~:h¥::::: •::::::~:t:~~:::::: :::\t:~:;:;:~:::: +0. l2S
::::::::~:2:~:0::;:::: ::::::~:E1:::::::::::: .• o. 12S
·:::::::~~:;:~:~:::: :::::::::~:f~:~;f: ::::::~:z:~:cf:::::::::.
~~i;" . ......A.a.~·
TIWfSMIBSUII LINC111 • 27.0'
ULATIVI PCJIIR LBVIL (cll:l) IN IIORUCIITAL DIIT.AHCII or M.Ai.
:!;2.0' ±l ·'' ;!:l.O' liPPU
~ :.::i:u···lW .. - . . . : '/ ~ ~ ::::1:1s:w ··- ., .. ' ~~ ~~ v~ ~ ~ Y.: 0V~,~ ~// :-.,.-..,
w ~~[/~ ~ H~ 2'ir.; Jl,><;,.
~ f)V l", ?i :;::~:f::»s:::::::
~ :./
·:::::~:2::;:~:::::::::: .. ~
~ ~......: :::::~i~:u:::::;::::: +.2SO
~ V;(% }' -.zso
~'" :::::~:i:~:ii:::::: +.125
~z z :::::~t{~~::::::: -.125
~~ ~w +.l2S
~~ ~~~ '? 09'. -.US : .. :)·:o·:·~ ··- ·. ··: t'/. ~0 vA ~'0:. +.125
:::.:):.:5::~~ ~~ ~ (~ -.125
TI.&IIBKIIIIOH Lltr:Til • 2S.O'
IILATIVI fOII!R LIVlL (db) IH HORIZONTAL DIITANCII 0~ HAl.
;!2.0' ,:!'l. S' +1.0' atPJU
&/##/h ~~ ~ t%0'/iV~
:~ ~ $: :'::C x K9 ::~!(i~:<: - .12~
~~ ~~~~ij($~
Figure 21 CHAMBER EVAWATION
FREQUENCY: ___ 3·_2_s_c1_1z ________ __
TRANSMITTING HORN SECTION:. __ 03_
RECEIVING ANTENNA:_st_a_nd_nr_d_c_.a_1"-
Horn (Narda Hodel
·DATE: _______ s~t~2l~/~66~----------
NOTES:
~ ~ (: ~::::::::)
• 0.5 • 2.S
• 0.5 • J.OO
• o.s. 3.5
• 0.5 - 4.0
• .! t.O db
• !: I. ::!5 dh
~ !: 1. 5 db
• !: I. 7S db
~teAL
:ANC!
2.0'
1.5'
l.O'
:n o.o
t.O'
I .1.5 1
2.0'
71C~l.
:ANC!
2.0'
1.5'
l.O'
rtR 0.0
1.5'
KIN
KIN
MIN
KIN
KIN
MIN
HIN
MAX
KIN
MIN
MAX
MIN
HlN
KIN
MIN
MIN
T1WISMISSION L!NC111 • 23.0'
RILA,'IVI PalER LEVEL (db) IN HORIZONTAL DISTANCES OF
~2.0' !l.S' ~1.0
.. . ........... . ::::::+:o:~i~:::::: ::::t:a::::i:t:::::: ·············· .............. . ::::::~:2:~::ii::::: :::~::}::::i:s::::::::
HAl.
RIPPI.!
+0. 75
-0.5
+0. 75
-0.75
+0. 75
-0. 7S
+0.5
-0.5
-0.75
+0.5
-0.5
+0.5 -0.5
TRAN8MISS10R LENGTH • 26.0'
RELATIVE POWER LEVEL (db) ~H. HORIZONTAL DISTANCES OF: MAX:
_±2 .0' _:!:1. 5' ~1.0' RIPPLE
........................ :::.:t~::~s:: :;.~~;~:s::: ::.:~;:z:s:::: +0.5"
:::.:t~o::::::.:t;o:::: ::.:1;o::::: +0.75
::;.;z~:n:: ::.:a:r.s::: :;..:a:2:s:::: -0.75
~~~·,)(~ :~2:o::::: -0.5
~~%', J't.V.l<.. i0.75
TRANSHlSIUOil LP.W-;TH • 23.5'
RILATlV! PallR LIVEL (db) IN HORlZOUTAL DISTANCES Of
~2.0 1 ~1.5' ~1.0'
r. :: ~:~; P.::: ::::::~:{::(;::::::::
:: ~~-~~:~:: ::::::~n::::2f/:
MAX.
RIPPLE
-0.5
+{),5
-0.5
TRANSMISSION L!HGTII • 26. S'
RELATIVE POWER LIVBL (db) IN HORIZONTAL DISTANClS OFr MAX,
RIP Pl.!
+1.0
-1.0
+0. 75
-0.5
-0.5
iO. 7S
-0.75
TRANSMISSION LKNGTH • 24.0'
lliLATlVI P~Jl UVIL (db) IN HORIZONTAL DISTANCES OR . HO.
!2.0' ~1.5' !1.0' RIPPLI
?.;X < f:{.-~: ·:::::~1~:0:::::::::: ::::::/t::::o:::::::::: +o. 15
· t~~ ~;'{):::: ::::::~l~:l~:::::: ::::::~::kz~:::::: -o. 1s ~~ :j):~~. :::::~:f~t.::::::::. :::\):~:~:-:>::::: +0. s 88:f: ~ ~:.:-: ::)·v?~:::::: ::::::~:t:;::~·~:>::: -o. s ~ -;., ~· :::::~::f::n:::::::::: ::::::::::t:::~::::;::::: +o. 15
~· KX~ ·':'-. :::::~i:::IS:::-::: :::::~:f:::s::::::::::: -0. 5
·~?;f'J-; < ::::~:{:1(<:: ::::F~:~Xt:> +{). 5
. ~~·1: (.-\( ::::~:i::s:::::::::: :::::~:(is:::;::: -o. s &(ti~ '·::::~:~):(::: :::::~:~{~t::::: +{). 5
~ ~~· . :~ :::\:h:f::::::: .:::>:t:~~:::::::::: . -0. 5
~ . ~ ~ :::\~~:~i::::: ::::::~~~:~!:\> +0. 2 5
...,-... c::- . ~ ::::::~:x:::i::::::::: ::::<t::::o::::::::::: IX: : i~· :::\{{:~:::::::::: ::::\{1:::5:::::::::: ffi. s ~". t~~~ :::::~:;:~:~{::::: ::::::~::()f:::: -0.5
TRAHSH18910N LINCTR • 27.0'
RILAnVI POWER LEVBL (db) IN HORIZONTAL DJSTARCII OF MAJ.
±2.0 1 ~1. 5' !1.0'
:::::~:f::~:::::::::::
~ ::::~::r~:n:::::::::::
l'\.-". .. ''1. ~J.~\.'\..f.Nfi...~.?VY: :.;.Q;~::::
~~ : :. 2; 25 : : .
~;.-:~ ~ :>cs:::::
RlPPLI
+0. 5
-0. s +O. 1s -0. 7S
+0.5 ..:o.s +0.5
-0.5
+0.5
-0.5
+0. 75
-0. 75
+0.5
-0.5
TRA~SJQ!ISIOH Ll~nt • 25.0'
IIUTIVI I'O'J!R UVlL (db) IM DOllZONTAL Dl8TANCl8 0~
+2.0' !1.5' !1.0'
figun• 22
CIIAHRER EVALl'ATJON
K.U.
UFPtZ
FREOUENCY: ________ 3·_4_5 _c_11z ______ ---
TRANSMITTING HORN SECTION: Dl
RECEIVING ANTENNA: __ Ah_s_ur_b_t'r __
OATE: __________ s_;2_2_1_66--------·------------
NOTES:
niiOIDliD. +0.25- 2.25.! 1.~5 dh
~. +0.~5- 2. 75. ~ 1.5 d~
•
~ +0 '5- 3.25.! 1. 75 J~ ~ +0:;5- 3.75.! ~.0 d~ w +0.25. ~.z~ • + !.15 dh
~~ ~I .. OJ 0\ I
()Q ()\ "' fl) I I oc
w~.,
00 N C
• f
L
I
2.0 1
1.5'
1.0'
0.0
1.0'
l.S'
2.0'
L
I
2.0'
1.5'
1.0'
0.0
1.0'
1.5'
2.0'
MIN
KIN
MIN
KIM
HIN
KIN
KIN
KIN
'MAX
KIN
MAX
KIN
HAX
KIN
MAX
TRANSM1S810N LENGTH • 23.0'
·uunn Pawn LEVEL (db) IN HOR~ZONTAL DISTANCES OP MAX.
,:t2.0' ;!1.~ 1 _±1.0 RtPPLB
TRANSHISSIOH LENGTH • 26.1'
R2LATIV! POWER UVZL (db) N HORIZONTAL DISTANCES OF: MAX.
RlPPLB
+0.75
-0.75
+0.75
-0.75
+0.75
-0.50
+0. 75
-0.75
+0.75
+0.50
+0.5
-0.5
+0.5
-0.75
TRANSHlSIION LINCTH • 2l.S'
RELATIVE JIOI!R LIVEL (db) IN HORIZONTAL DISTANCIS OF
±2.0' ±l.S' ,:tt.o•
~~~;/~ Vh (/, ~~-~~: , <:~t>:·
)o; ~, : ~ ~ ~ :::;:~t~Q}::
·~ ·~ ' ~ ::::=~~:~;2~:::: ,..: \ ~ ~ ::::::~:~~:};~::::
I~·"'~~ I? ~ ~ ~ :::;::~:({}$:} l" ~ ~:::}~X;::~::::::
MAX.
RIPPLE
+0.5
-0.5
+0.5
-0.5
+0.5
-0.5
+0.5
-0. 7S
+0.5
-0.25
+0.5
-0.5
+0.25
-0.25
TRANSMISSION LIRGTH • 26.5'
R£t.AnVB POW'BR LBV!L (db) IN HORIZONTAL Dt8TANCI8 OPt MAX,
,:t2.0' !1.5' !l,O' RIPPl.!
:::.:r.:s::: 1?-?>vUh~ ~·/.'l~ +o. 75 . . . . . . . . . . . f'l/"..tY::"/ /..t , ...r. v,J.?. ~'.I
TRANSHl9610N Lltllcnf • 24.0 1
RILATIVI POW'!R LEVEL (db) IN HORIZONTAL DISTANCES OJ HAl.
:!;2.0' ±1.5' .:tl.O' RIPPLI
:::.a:.:Js:· :~:t:75::·::;..:t~1.5::: +t.o :::~~:.:o::: ::-:4;Q::: ::~J;:~s::: .o.1s w~~'» -~ . . <.<: !~ ~ +o.s ~~~:><~~~~~ ~~ ~ -0.5
·/ L;(}Z ~:> ~- ~-:)(~' ~,: ~ ~ +O. 5
g v. ~-~/· "~: yl~·-· ~ ~ -0. s • -~~£;:~:: :;:~ ·~ ~~ ~ ~;-: ~ +0. 25
ll, .;, ;, i ~~~~~~ ~ -0.25
~!:~:.-~~.-~: ">;.: -;. • '-'I~ ~ :\~ . +o. 25
~i'~ }: Xll.. ~ >:~ ~ ~~ -0.50
w~-o/ ·>l~ ~ ~ ·t-{).25
w~~ ·~ .. .-"~-~ ~ ~ .o. 25
:::~:cs::: ::~r.:s:::: ::.:r.:s:::: -H).5
.::::j:s::: ::~~:_:o:::: ::.:~:.:o:::: -o.5
1'RA.HSM1SSION LINC'l'R • 27. 0'
R!LATIVI POWER LBVIL (db) IN IIORIZONTAL DlBTANCII OP HAl.
:!;2.0' :!;1.5' :!;1.0' RIPPLI
·: :;.:t; s: .. : :.; r.:s:::: R-.6t:,: ·~« +o. 1s .::3 .. :2·c;: ....... o···· ·-:'X'.l=~a.~ -0 .. 75
• .,. • .,) • • ·- LJ-.· • • ' ·-::~'){· ~~'·.~~
f~M r:.('"t'l'"i:!><x~~tl-X:f.'.-:1}}~ +0.5
@<.~ ~<~. ~:,. ·;::"<V.i}·:~ .:o. 5
~~// ·r,?.~' -~-~'Y x~ ~· +0. 75
~~ ~~~~ ~: ~) ;~ ;0 -0. 7')
~w ·· '.,)., r:··..., ~· ~~Q +0. 5
~00 ~ : .... 1;·::- ~=> =~ -~~ -0.5'
t~y;,:,ij: ,,. J'. eye~' < ~X +0. 5
~ ~-< 0·: ·~ ~~t~ ~:r~- -0.75
~:..-,...~·;·X ~· ~ .. ~ -~l;.:. ~ +0. 5
~'/: ~ .. '~ ~ ~r-;x ~~ ~ -0.5
:::~~.:25=: ::~2:.:ts:::r;::~~;~o ~ +O.s
TRA1118Hl£810N LIICTH • 25.0'
RIUTtV! POl!'l t.EV!L (db) 1M ROllZOHTAL DISTANC!S 0~ HAl.
±2.0' !1.5' +1.0' IUm.l
Figure 2)
CHAMBER EVALUATION
+0. 75
-1.0
+0. 75
-0. 1~
+O.S
+0. 5
-O.S
+0.5
-0.75
+0.5
-0.7)
+0. 5
FREQUENCY: ____ J_.~B~G~Hz~-------
TRANSMITTING HORN SECTION :_0.._1 _
RECEIVING ANTENNA: Ah:wrtu::r
backed dlpo\('
DATE: Bt2Jt66
NOTES:
0. 0 - 7. 0 • ! l. Odb
0.0. 2.5.! 1.25d~
0.0- J.O •! l.Sdb
0.0- ).5-! \. 75dh
0.0 • 4.0 • ! l.Odh
MR.T-4-046 J QM-66-072 ---..:1,_1~ . Page 40 ~ u h - -~II 'tt! . : · . ..!.._;,_L_H--1 +r ~[ '-rii' ::=r.:~-l-+ :-r:-+-t++ 1, -H-11H-tt·!1=t"tt:l ' I I I .. ; _.:.._ ·~· '!-, I '. :-r- .L ,_ .. ' I I I
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OQ=!=L lf--J-J..++-~H++-HH-t. -t.lDt..LI,::: .... !:~ 1l:::::::: :~-~~~:~ :-: 1t~~ . --~- ~~[~_1-~:-l:..i; ~i=t:~+=H-+++-H~t-ttj:t' :t:ttJ::J r-ro:~u~~~+H++H-H,-H,:,cnt·C:Jt I ~-:~~--· ~-~~~·j'~~~;~~·=~~~~R+~~±~~±~~t~~ I I I I : I I ! 1 'I ! ; [' - ~ . . ' . ' -: ' It • ; ._
fTT I l I .1 I I I I I: I I I I I· I I I I I I I : I l I ; I Ill I II: I I ' II H;. :l-t -~- l I I II I I J I I' . I I J l I I ! I I .
Tn. Jonna Hopkin• UnivMsity .PPLIE.O P'HYIICI LABOAATOU'
sa .... , s"'·in<;~. M.ryl•l"M:f
.,5&8&= MRT-4-046 QM-66-072 Page A 1
l-
APPEl'-tTDIX A
Transmitting Horn, Design and Test Results
INTRODUCTION
Th~ anechoic chamber specifications originally called for a
four foot cubic quiet zone; however, it was determined that a quiet zone
3' wide x 2' high x 1' deep would be suitable for two test samples in con
tainers side-by-side. Wit~ a minimum transmitted power of 200 watts, a
power density of 2 mw/cm2 ± 1.0 db was required in the quiet zone. To
allow for a margin of safety, a uniform illumination (within± 1.0 db) in
a 4 1W x 3'H x 2'D quiet zone was the design goal for the transmitting hor~
antenna.
A conical transmitting horn antenna design was chosen because it
has an H plane toE plane beamwidth ratio close to that required (4 to 3),
without the narrower beam in the intercardinal planes associated wi~~ the.
pyramidal horn antenna.
Because gain and beamwidth vary with the wavelength, the horn
design incorporates "add-on'' sections for the various incremental band
widths. This is discussed further under beamwidth considerations. The
first section includes a built-in rectangular to circular transition ob
viating the need for a separate waveguide transition. Figure 5 in the main
section of this report is an illustration of the transmitting horn.
BEAMWIDTH CONSIDERATIONS
The geometry for the horn illumination of the quiet zone is shown
in the following sketch.
~D:2.o'--f
~~r:T I . I 9 . -t-' ~ -. r-, fi
l~·fllllt---23.01 ------:llillol-.f . I tj 'Tit:AL RIZArtON
'--~-~ /1 Q/..11/:T l.: 20NE
n,. Johns Hopkint Uni.,..rtity A•PU£0 PHYaiC8 U8011ATOIIT
sa_.. Spfin;, ~1-.;
-¥lUAU a Z.lRT-4-046 QM-66-072 Page A2
The chamber specifications called for a maximum of .5 db (~ .25 db)
change in amplitude due to reflections from the walls. This value, added to
the .75 db (~ .~7 db) change in amplitude due to the change in transmission 1 .
length (i? loss), dictated that the change in amplitude due to the beamwidth
of the transmitting horn could not exceed .75 db in order to meet the design
goal of± 1.0 db change in power density in the quiet zone volume. l .., e - o above sketch, then, the .t5 db beanwidth is 2 2 = 2. tan 1_ = 9.2.
25
From the
From
the figure in reference 3, the ratio of the .75 db beamwidth to the 3 db
beamwidth is .5/ Thus,
eH <. 75 db)
eH< 3 db) = .5 eH (3 db)=
9H(.75 db>
.5 = 9.2 .5
..,
=
The .S-Band frequency range from 2 to 4 GHz was divided into e~ght
··increments, each representing approximately 10% of the band, in order to keep
the beamwidth (and gain) nearly constant. To compensate for this ten percent
bandwidth, the design beamwidth was increased by ten percent, resulting in a ·
desired H plane 3 db beamwidth of 20°.
The horn aperture diameter in wavelengths(D/X) was determined from
the approximate expression from the H plane beamwidth (4)
- 70 9H(3 db)= D/"A
0 For 9H(3 ~b)= 20 , D/X = 3.5. Starting at 2.0 GHz, the approxi-
mate 10% incremental frequencies, wavelengths, and the diameter of the horn
section computed from D/"A = 3.5 are shown in Table Al. Also shown in this
table are the lengths of the various sections computed from the geome~ry in
the following sketch.
~ D 2 · 1
(2) X 2¢
For D ~ 4X ¢=1 4
(chosen) ,_, ___ ......,,.... __
e:- --L=-Sf>,7S''-'-----..::~~-. L = BJ...
1966, Page 174.
Tn. Jo..,,, Hoplr.int Univ.,aity "PLIED PMYSICI LA8011ATORY
Silvttt Spr:;'lg, M.tryl.w,d
......
~ QM-66-072 Page A3
Thus L = 8~ determined the lengths of the various sections
as tabulated.
TABLE AI
Horn Dimensio::!s
Freq. ).(in.) Diameter (in.) Section L (in.) D = 3.5). Designation n
2.00 5.8 20.00 DB· 21.5
2.20 5.35 18.75 D7 17.5
2.45 4.80 16.75 ·n6 14.0
2.70 4.35 15.25 D5 10.5
2.95 4.00 14.0 D4 7.50
3.20 3.70 13.0 D3 5 .. 25
3.55 3.35 11.75 D2 2.25
3.90 3.05 10.75 Dl 0
The recommended frequency range for S-Band WR 284 waveguide is
2.6 to 3.95 GHz, therefore horn sections larger than D6 may not be required.
However, should higher power densities be needed (over smaller areas) horn
.sections D7 and DS, and two additional sections, D9 and DlO were constructed . •• The diameters for D9 and DlO are 22.5 "and 24.5", and the lengths are 26.75
" and 31.75 respec·tive ly, based on the same criteria as the other sections.
GAIN REQUIREMENTS
The above analysis assumes an aperture with sufficient
gain to provide a pow~r density of 2 mw/cm2 for a minimum of 200 watts
of transmitted. powe~.. Reference 5 gives the gain of a conical horn as
4nA G (db) = 10 log (7) - L, where L is the loss term (in the reference figure)
.versus the phase deviation at the aperture edge. For the selected phase
deviation of A/4, L = 1.5 db; and for D/). = 3.5
rrD 2
G = ~~) - 1.5 db = 20.85 - 1.5 - 19.4 db
(5)Antenna Engineers Handbook H . .Jasik, Ed. McGraw Hill (1961) Chap 10-4
The Johns Hopltin1 Univeraity PLI[O PH'U'CI LABORII.TORY
Sil.,.• • · .,9, M.rylend
The power
Pd =
density pr
= Ar
is PTGT
where PT 200 watts 4nR2 =
GT 19.4 db =
R 24 ft
Pd = 2.6 mw/cm2 , which is adequate.
MEASURED VERSUS CALCULATED VALUES
(min)
87
911Mi1 n MRT-4-046 QM-66-072 Page A4
The calculated gain~bove) was 19.4 db at the design frequencies,
which included a 1.5 db l~ss ·due to efficiency and phase error. The meas-'
ured gains at the design frequencies are t~bulated below along with the dif-
ference between the measured and calculated gain (6G).
TABLE A2
Measured versus Calculated Gain
Horn Design Measured Calculated ilG Section frequency Gain Gain
Dl 3.9 20.3 19.4 +0.9
D2 3.55 20.0 19.4 +0.6
D3 3.20 19.7 19.4 +0.3 D4. ·2. 95 19.7 19.4 +0.3
D5 2.7 19.6 19.4 +0.2
D6 2 .. 45 19. 4_(es t) 19.4 +0.0
From this table, it can be seen that the measured gain is very
slightly higher than calculated. This is due in part to the beamwidth being
slightly narrower than the design value; and in part to the phase deviation
at the ~perture edge being less than A/4, and consequently, the loss due to
phase error and efficiency being slightly less than the 1.5 db allotted.
Table A3 below compares the measured and calculated 3 db beam
widths, which again are in good agreement. These values indicate that the
expression for the H plane 3 db beamwidth is more nearly
for theE plane SE ~ 55/DA ..
;
- 68 98 (3 d~ = D/A and
e Johl'lt Ho-pkii'IS Univei'lity .I £0 PHYSIC" L.ABO .. ATO•Y $il'¥et S~···"'l, Maryla~
TABLE A3
Measured versus Calculated E & H Plane Beamwidths Calculated Measured Measured
Plane 3dbB.W 70 Horn Frequency H 98 (3db )=D/''A. E Plane 3dbB.W Section (GHz) (Degrees) (Degrees)
Dl 3.9 18.9 20° 15.8
D2 3.55 19.3 20° 15~7
D3 3.2 '19. 7 20° 15.7
D4 2.95 19.6 20° 15.5
D5 2.7 19.5.· 20° 15.5 ,.
D6 2.45 19.5 20° 15.5
"Ail£! MRT-4-046 QH-66-072 Page AS
Calculated 60
9E (3db )=D/1-.
17°
17°
17°
17°
17°
i/0
It Johnt Hopkint Uni.,.nity .lED PHYSICS uaORATORY
Sil"'"' Sr"'ing, ,M.tryiM~d ,
APPENDIX B
Sleeve Dipole Antenna
Page Bl
A dipole was chosen as the field probe antenna for the chamber
evaluation in order to observe virtually all of the reflections from the
walls (and the ceiling and floor), which contribute to the perturbation of
the field in the chamber. The sleeve (or skirt) dipole design was selected
because of its natural configuration for an upright power monitor of a ver
tically polariz"ed field, and becaust ~f its ease in construction utilizing
the APL 5-spline semirigid coaxial cable which was available; the dipole
probe tip simply screws into the cables hollow.center conductor. The di
pole is illustrated in figure Bl. This figure gives the pertinent design,
dimensions which were arrived at empirically us{ng the basic tenets set
forth by Silver(6).
Figure 13, in the main section of this repor~ illustrated the
fixed monitor version of the sleeve dipole used as a power monitor in the
~hamber.
Figure B2 illustrates the "gooseneck" version used to evaluate
the chamber.
The VSWR of both versions is shown in figure B3. These values
include the mi-smatch from the Type N to 5-spline cable transition. A sur
prising feature of these dipoles is that the VSWR was less than 2:1 from
2.6 GHz to 11.4 GHz (the limits of the then available equipment).
( 6 )M. A Th . . d D . S .. Ed 1crowave ntenna eory !£_ es1gn . Silver, . MIT Rad Lab Series, Vol 12 McGral~ Hill (1949) Chap 8.2
...,, : ... ~-·---• --·-:--:_, ____ ,:,,.·«-lOr ... th.o> tali 1 ddeiUie of the United Stat.H wiihio t.he rneani~ of the Eapion.a,n l.a"'-., Title 18 . • . • . :~ ---'-a .. ; ...... """- •·-
1.
At • Hopkin• Univeraity .MYIICI \.A80RATORY
,. Spring, Mllryland
OPERATIONAL PROCEDURE FOR
PROJECT PANDORA MICROWAVE
TEST FACILITY
MRT-4-045 QM-66-071
Prepared by
E. V. Byron
October 1966
T
""' · Hopkins Univertity
YltCS LAaORATORY ,prin;, Mairyland
ABSTRACT
.MRT-4-045 QM-66-071
This report describes the operational procedure for the Project
Pandora microwave test facility. It. is intended primarily for non
microwave oriented technical personnel ~o enable them to operate the
facility·with a minimum of training. Included is the Turn-On, Turn
Off Procedure, the procedure for measuring transmitted power and power
density, and a description of the power monitors.
-i-
... ,_ ..
AP Hoplcifts Uftlw,.lty
AVIICI uae•A JO•V .( Spring, •ryland
Section
I.
II.
III.
IV.
TABLE OF CONTENTS
MRT-4-045 QM-66-071
Title Page
Introduction 1
Equipment Operat"ion 1
. A. .Pr~liminary· Turn~ On Procedure 2
B. Operational Turn-On Procedure 3
c. Turn-Off Procedure 4
Procedure for Selecting Horn Sections, and Power 5
for Desired Power Density
A. Design Frequency Range for 5
"Expandable" Conical Horn
B. Horn Section for a Reduced Quiet.Zone 6
Microwave Power Monitor 7
A. Monitor No. 1 7
B. Monitor No. 2 and Alternate Monitor No. 1 8
- ii-
• :J ..
1 Hopt&iM Uftlwnlty AP. !MYIIC. LAaoaAro•Y
., .. ver Sprino • .._,,and
Figure No.
1
2
3
5
6
LIST OF ILLUSTRATIONS
Title
Pandora Microwave Equipment Racks
Pandora .Microwave Equipment - Functional Block.Diagram
Power.Density per Watt Transmitted for Each Horn Section
High P~er Monitor - Meter Reading . versus Transmi·tted Power
Received Power Density-Monitor Channel Number 1
Table of Horn Section Aperture Diameter
-iii-
MRT-4-045 QM-66-071
9
10
11
.. ·.·
12
13
14
.. T Hopkiftl \Jftivenity
APP 1YI1CI LA•o•ATOaV ..... ... f Spfinv, tNryiMKI
I. INTRODUCTION
MRT-4-045 QM-66-071 Page 1
This report describes the operational procedure for the
Project Pando.ra microwave test facility. It is intended pri
marily for non-microwave oriented technical personnel, to
enable them to operate the facility with a minimum of training.
Sect.ion II of this report del.:neates the· basic turn-on, turn-off
procedure for the equipment. Section III describes the procedure
for determining which of the "add-.on" sections of the expandable
conical horn to use, and the power requirements for a desired
power density. Section IV describes the _p·owE!r monitors in the
microwave anechoic chamber.
The microwave equipment for Project Pandora is assembled in
the four equipment racks illustrated in figure 1~ Rack No. 1
contains the Spectrum Analyzer R.F. and Display sections. Rack
No. 2 contains the auxiliary low-power microwave generation and
modulation equipment. The equipment in this rack is not inter
connected (nor is the spectrum analyzer). Rack No. 3 contains
the primary low power microwave generation and modulation equip
ment, and the necessary monitoring and recording equipment. Rack
No. 4 contains the high power microwave amplifier and power sup
plies. The interconnection of these two racks, with the "expandable
horn" transmitting antenna in the anechoic chamber, is shown in
figure 2 which is a functional block.diagram of the microwave sys
tem.
II. EQUIPMENT OPERATION
The following instructions pertain to the operation of the
equipment assembled ·in equipment racks 3 and 4 with reference to
figures 1 and 2.
Note: For operation of the various individual pieces of
equipment, refer to the manufacturers' operation
manuals which are available at the test facility.
Hoplllna Uftlwraity tvatea LAao••ro•v Sprift9, M.lryland
MRT-4-045 QM-66-071
Page 2 A. Preliminary Turn On Procedure
~: Connect the ·proper transmitting horn section for
the required frequency and power·denstty as outlined
in Section III of this procedure.
1. Equipment·!!£! Number 4
a. Turn on water supply. Pressure should be between I
15 and 50 psi.
b. Turn on low voltage A.C. power supply. Set Heater
Vol~age to 6.3 volts.
c. Turn on D.C. power s~pply (solenoid power). Set
to 33 volts.
Note: Under no circumstances should the solenoid .
be operated without water cooling or perma
nent damage will result. If the over current
light is energized, the door interlock is
·open or there is insufficient water pressure
or solenoid current.
d. Set the Cathode Voltage switch on the high voltage
power supply to the Burn-in position and turn on the
high voltage.
Note: There is a 3 minute delay before the high
voltage comes on. Allow 15 minutes warm-up.
2. Equipment Rack Number 3
a. Turn on A.C. power to rack number 3.
b. Turn the Grid Control on the Alfred 5-6868, 10 watt
TWT amplifier to -250 volts. Turn Helix Control
completely CCW.
c. Turn HP692C Sweep Oscillator to Standby position.
d. Turn on power to all equipment, allow 15 minute
warm-up.
n APP
HopkiM Uniwnity 'fltC8 ueOIATO•Y
,pr inv. M.tryl~
MRT-4-045 QM-66-071
Page 3
e. Zero all HP431C power meters. For. maximum ac-·
curacy, the power meters should be "re-zeroed1'
periodically. Refer to the ·HP431C instruction
manual.
f. Turn Sweep Oscillator Output Attenuator and TWT
Output Attenuator completely CW (max. attenuation).
g. Set HP692C to desired frequency and connect for
desired modulation.
Note: Refer to the instruction manuals of the HP692,
HP8403A, and the HP3300A for the possible
modulation options and their settings. If
the auxiliary low power R.F. generation and
modulation equipment is to he used, refer to
the appropriate instruction manuals for pos
sible interconnections and operating instruc
tions.
·h. Turn HP692C to Operate position.
B. Operational Turn On Procedure
1. Equipment Rack Number 4
a. Set Cathode Voltage switch to the . l/3.3KV position
and observe high voltage and current meters.
Note: Do not allow high voltage to exceed 3250
volts and t~e current to exceed 560 rna.
b. If necessary, adjust high voltage screwdrive adjust
ment for high voltage meter reading of 3250 volts.
DO NOT EXCEED 560 MA. CURRENT.
2. Equipment Rack Number 3
a. Turn Helix Control on Alfred 5-6868 'IWT completely CW.
b. Turn Grid Control on Alfred 5-6868 TWT completely CW.
..•
The APP'\.
.. "iopkiftl Uniftraity
·aac.t LA.ORAto•Y lift9, Mlrylend
MRT-4-045 QM-66-071
Page 4
c. Adjust Sweep Oscillator Output Attenuator for
maximum power output as observed on TWT Monitor
Power Meter. Lock in position.
d. Adjust TWT Output Attenuator for the required
transmitted power as observed on the TWT Monitor
Power Meter. Ll•ck in .position.
Note: The transmitted power required for a desired
power density can.be determined from figure 3
·and Section III of this procedure.
The transmitted power can be determined from
the meter reading and figure 4; (High Power
Monitor, - Meter Reading vs. Output Power).
DO NOT EXCEED 250 WATTS TRANSMITTED POWER FOR
EXTENDED PERIODS OF TIME WITH THE INITIAL TUBE
SUPPLIED.
e. Set the monitor switches on the monitor switch panel
to connect the desired function to be .monitored to
the strip chart recorder. The normal setting of these
switches is TWT Monitor to the recorder channel No. 2,
and Monitor Channel No. 1 to recorder channel No. 1.
f. Connect "Available Inputs" to the scope or the HP415
as required.
C. Turn Off Procedure
1. Equipment Rack Number 3
a. Turn 10 W TWT Output Attenuator max. CW (max.
attenuation).
b. Turn Sweep Oscillator Output Attenuator max. CW.
c. Turn Grid Control on Alfred 5-6868 10 Watt TWT to
-250 volts. Turn Helix Control completely CCW.
..
T' API
Hopkint \hllveraity 1\'ttea LA•o•.uo•v $prinv, MA!ryland
MRT-4-045 QM-66-071
Page 5
d. Turn HP692C Sweep Oscillator to Standby position.
·e. Rack powet may now be turned off.
2. Equipment Rack Number 4 \
a. Set the Cathode Voltage switch on\high voltage
b.
c.
d.
e.
power supply to Burn-in position.
I Turn off high voltage . .'
Turn off low voltage A.C. power supply.
Ttirn· off D.C. power supply.
Turn off water supply.
III. PROCEDURE FOR SELECTING HORN SECTION AND OUTPUT POWER FOR DESIRED
. POWER DENSITY
A. Design Frequency Range for "Expandable" Conical Horn
The microwave facility was designed such that a suitable
quiet zone - minimum dimension, 3' wide by 2' high by 1' deep
for two "test samplesu side ·by side - would be illuminated
uniformly a + l.Odb power variation in the quiet zone was
the design goal. The quiet zone, as discussed in this report,
starts at a transmission length of 23.0 feet and is symmetric
about the chambers horizontal and vertical axis. These quiet
zone dimensions, therefore, set the beamwidth characteristics
of the transmitting horn; and a conical transmitting horn with
"add-on" section was designed: to give maximum gain with the
required bearnwidth over the S-Band frequency range. Under
these conditions, figure 3 shows the "design frequency range"
for the appropriate sections (D1 through D6). This figure is
a plot of power density (in rnw/cm2) per watt transmitted - Pd/W -
versus frequency, for each of the horn sections. It can be seen
that, for the design frequency ranges, Pd/W is 1.6xl0- 2 mw/cm2 ± 10%. watt
Thr APPI
·•opkina Ut\i-nity · tltCI uao•AToaY
.pring. M.tylend
MRT-4-045 QM-66-071
Page 6
Thus, for 250 watts transmitted, the power density in the
quiet zone is 4.0 mw/cm2 ± 10%.
1. .. To determine specifically the transmitted power ·required
for a desired power density (at a given frequency in the
design range):
2.
a. Determine Pd/W tor the known frequency and horn
section from figure 3.
b. Solve: Pd/W X Power = Power density
Power = Power densit~
Pd/W
3.0 GHz, density ' 2 c. Example: At a power of 2mw/cm
is required. (Horn Section D4)
Pd/W -2 from figure 4. = 1. 58xl0
Power 2 126 watts = - -2 = 1.58xl0
To determine .power density from a known transmitted power:
a. Determine Pd/W for the known frequency and horn
section from figure 3.
b.
c.
Solve: Power density = Pd/W x Power
Example: At 3.5 GHz, 200 watts are transmitted (Horn
Section D2).
Pd/W = 1.56xl0- 2 from figure 3.
-2 2 Power density= 1.56xl0 x200 = 3.13 mw/cm
B. Horn Section for a Reduced Quiet Zone
To increase the versatility of the test facility, additional
·"add-on" horn sections were designed to uniformally illuminate suc
cessively smaller quiet zone volumes with incr~ased gain. The
determination of the quiet zone volume is dependent upon the beam
width of the v~rious sections and is beyond the scope of this re
port. Suffice it to say that, at the upper end of the frequency
band (3.95 ~Hz) horn section D10 will essentially illuminate uni-
T' "'"' HopltiM Uftiwrtity Af •MYIICa LAaCIIAto•v
S.Wint, M.ryland
MRT-4-045 QM-66-071
Page 7
formly a quiet zone large enough fo·r a single test sample -
1.5'W x l'H x l'D. At this frequency, n10 gives the maximum
power density obtainable for the system. As the frequency is
decreased, horn section n10
will uniformally illuminate a
proportionately larger volume with reduced gain.
1. The power required for a desired power density can be
determined as in Al &hove.
a. Example: 2 10 mw/cm power density.is desired at
3.95 GHz (Horn Section n10)
Power = Power Density
Pd/W
. Pd/W -2 = 3.83 x 10 from figure 3
Power = 10 -3 ° 260 3.83 x ·10 = watts
IV. MICROWAVE POWER MONITORS
In addition to the high power TWT monitor, there are 3 power
monitors in the anechoic chamber. Two of these, Monitor #1, a
standard gain horn, and Monitor fF2, a· sleeve dipole, are connected
to the. HP431C power meters in rack number 3. These two monitors
may be switched to the Mosley 7100B strip-chart recorder (see figure 2).
The third monitor, alternate monitor number 1, is a sleeve dipole and
has an available output as shown in figure 2.
A. Monitor Number 1
Monitor number 1, the standard gain horn, is the primary
"down stream" power density monitor. Power readings on the
Channel No. 1 power.meter can be converted to power density
at the point of measurement with reference to figure 5.
Note: It must be reemphasized that this monitor, in conjunction
with .. figure 5, measures the power density ~ the point
where the monitor is placed in the chamber, and not the
power density at the center of the quiet zone as determined
in Section III.
14' "' Hopkina Univenity •MVIICI LAeORATORV ' S.,inv. ~rvl•nd
B. Monitor Number 2 and Alternate Monitor No. 1
MRT-4-045 QM-66-071 Page 8
These monitors are available to measure relative power
density and for the observation of signal waveforms at any
point in the chamber.
By placing monitor number 2, with its alternate monitor
line connected, at a point of known power density (previously
determined as in Section III. or IV A above), and placing alter
nate monitor number 1, at any other point in the chamber; a
gross measurement ·of power density can be made by observing
the relative readings. Due to the nature of the chamber re
flections, the power density measured in this manner can be in
error by± 2 db; ~owever, as a "gross" power density measurement
technique, these monitors are useful sinc.e they are lightweight
and easily movable.
......
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PANDORA MICROWAVE EQUIPMENT FUNCTIONAL BLOCK DIAGRAM
FIGURE 2
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QM-66-071 Page 11
Fig. 3 POWER DENSITY PER WATT TRANSMITTED FOR EACH HORN SECTION
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FREOUENCY - GHz
ARROWS SHOW FREQUENCY RANGES f'f\D 't 1 tll- ~•u - ,1"' 1"\t·ll,...,. ""• .. .,
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QM-66-071 Page 12
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TO MEASURE TRANSMITTED POWER: ADD CORRECTION TERM TO TWT MONITOR POWER· MEiER READING.
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CORRECTED METER READING 2.38 dbm sO: 140 Watts P1 · ·
· TO SET TRANSMITTED POWER:
~----
SUBTRACT CORRECTION TERM FROM CORRECTED METER READING WHICH CORRESPONDS TO DESIRED POWER. ADJUST POWER TO OBTAIN THIS VAL.UE ON TWT MONITOR POWER METER.
CORRECTED METER READING vs· TRANSMITTED. POWER
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TO MEASURE POWER DENSITY: ADD CORRECTION TERM TO METER READI'
Example: AT 3.0 GHz, CORRECTION TERM · .. 4 do METER READING = 3 . O.dt!m
CORRECTED METER READING = 4.4 dbm 4.4dbm * 3.0 Mllliwotts/cm2 ~
To· SET POWER DENSITY: SUBTRACT CORRECTION TERM, FROM MElER READING WHICH CORRESPONDS TO ·REQUIRED POWER DENSITY. ADJUST POWER TO OBTAIN THIS VALUE ON MONITOR CHANNEL N! t POWER METER.
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. POWER DENSITY ( Milliwillfs/ tm1}
J :
lt APP
Hoptlim Univenity ntcs uaoaAton·
.liprino. Mlryllltld
FIGURE 6
Horn Section Dimension
Horn Section Diameter (inches)
D1 10.75
D2 11.75
D3 13.00
D4 14.00
D5 15.25
D6 16.75
D7 18.25
Da 20.00
D9 22.25
D10 24.5
MRT-4-045 QM-66-071 Page 14
Af ' Hopkins Univ.rr.itv HYIICI t..ABOilATOilY
( Spring, M.tryland
External Distribution:
. p. Tamar kin
R. s. Cesaro/5
H. M. Grove
R. w. Beard
F. Koether
J. Sharp
MRT-4-045 QM-66-071 Page 15
The Johnt totopklna Uftiv.rtlty 1\Pr "' PHYSICS I.A80RATOIIY
r lpfinrg, Maryland
Internal Distribution:
R. E. Gibson/2
A. ~ossiakoff
A. M. Stone
J. w. Follin/2
J. L. Queen
T. c. Cheston
E. V. Byron
Archives/2
MRT-4 File
MRT-4-045 QM-66-071 Page 16
. , J~,, Ho..,lr.i"a U~$ity liD f'oHY:..oCS LABPIIIATOitY Sil""" Spring, ~land
External Distribution:
P. Tamarkin Copy No. 1
R. s. Cesaro 2
R. s. Cesaro 3
R. s. Cesaro 4
R. s. Cesaro 5
R. s. Cesaro 6
Ho M. Grove 7
R. w. Beard W/o enclosures
F. Koether W/o enc losure·s
..&Eifil& I~ MRT-4-046 OM-66-072 Page Dl
i
