TO - Defense Technical Information Center · gether with typical antenna patterns and VSWR data...

UNCLASSIFIED

AD NUMBER

AD881468

NEW LIMITATION CHANGE

TOApproved for public release, distributionunlimited

FROMDistribution authorized to U.S. Gov't.agencies only; Test and Evaluation; 19 MAR1971. Other requests shall be referred toNaval Weapons Center, China Lake, CA.

AUTHORITY

USNWC ltr, 30 Aug 1974

THIS PAGE IS UNCLASSIFIED

-~ NWC TP 5099V - '..COPY 107

EVALUATION OF AIRBORNE TELEMETRYANTENNAS FOR USE IN UHF

TELEMETRY BANDS

QO by

V. R. Christenson

Systems Development Department

ABSTRACT. This report documents the results of a program conducted

Co [Z to evaluate experimental and commercially available UHF airborneantennas for use in the 1435- 1S35 and 2200-2300 MHz telemetry bands.

r ) The evaluation established that a wrap -around type antenna givessatisfactory performance and is adaptable for use in several differentID

~44.j L~..Jmissile configurations. The design and operational characteristics hjjIj~ j

each antenna evaluated in a missile configuration are presented, th Efgether with typical antenna patterns and VSWR data obtained durnq

the program.

Weals Of iflustrati tl~M4~ dOCUM~rit imay bei better, 'A -

p twicdi onDISTflIBUT'C'\ "I"

Ditiiin r t"t . ovn nics only.

opT OP Ote r ocu~ent must be reloned to:

NAVAL WEAPONS CENTERCHINA LAKE, CALIFORNIA *JANUARY 1971

pot

NAVAL WE'tAPONS CENTERAN ACTIVITY OF THE NAVAL MATERIAL COMMAND

W. J. Moran, RADM USN ,... ........................ Commander

H. G. Wilson ............................... . Technical Director

FOREWORD

As part of the Navy's scheduled conversion from VHF to UHF for test range operations,

the Naval Weapons Center conducted a program for the development of a universal

UHF antenna system that could be adapted to any missile and provide antenna patterns

that would give satisfactory air-to-ground missile coverage. Several different types of

commercially available and experimental wide-band UHF airborne telemetry antennas

were evaluated and it was demonstrated that a wrap-around type antenna, using stripliie

or microstripline techniques, is applicable to several missile configurations and offers

the best solution to operation in the assigned 1435-1535 MHz and 22C0-2300 MHz

telemetry bands.

This report describes the configurations and gives typical performance data of the wrap.

around antennas evaluated, and indicates the designs that are acceptable for the intended

purpose. The work was done during the period June 1967 to December 1970 under

AirTask A05-535-222/216-1/F99-05-01.

Released by Under authority of

L. G. GARMAN, Head ._.... -. IVAR E. HIGHBERG, Head

Instrument Qf---o.Divsion--. Systems Development Department

4 January 1971 WRITE 0AM 'K

...............-.........

....... l........ .. . .. .................

V ..............

N Technal Publication 5099

Publishd- .... ..... .. . Systems Development DepartmentManuscript ................ .30/MS 1-41Collation . . Cover, 14-leaves, -DDForm 1473, abstract cards

First printing .......... .... . . 215 numbered copies

Security classification ...... . . . . UNCLASSIFIED

_I

NV/C TP 5099

CONTENTS

Introduction.......................................IStripline and Microstripline Design..... . .. . .. .... . .... . .... .. 1Crossed-Slot Design.... .... . .... . .... . .. . .... ... ..... 2Antenna-Pattern Measurement Procedure..........................2

Summary of Test Results...............................3Haigh Antenna.. .... . .. . .. .... . .... . .... . .. .... .. 3Ball Brothers Antenna.. . .. . .. . .. .... . .... . .... . ... 4

Litton Antenna.. .... . .. .... . .... . .... . .... . .. .... .. 4NWC Corona (NWCC) Antenna... . .. .... . .... . .... . .. . ... S

Conclusions and Recommendations... . .. .... . .... . .... ..... . . 5

Figures:

1. Comparison of Stripline and Microstripline Configurations...............72. Crossed Slot in the Broad Wall of a Dielectric Loaded Waveguide..... . .. ..... 73. Missile Coordinate System..............................84. Test Setup for Pattern Measurements of Wrap-Around Antennas..... . .... . ... 8S. Haigh Wrap-Around Antenna...... . .... . .... . .. .... . .... .. 96. Haigh Antenna Installed on TM Section of Shrike Missile.... .... . .... . .. 97. VSWR/Return Loss of Haigh Antenna........................108. Haigh Wrap-Around Antenna Yaw Plane Pattern...................119. Haigh Wrap-Around Antenna Pitch Plane Pattern..................12

10. Haigh Half-Wrap Antenna.............................1311. VSWR/Return Loss of Half-Wrap Antenna......................1312. Haigh Half-Wrap Antenna Yaw Plane Pattern..................1413. Haigh Half-Wrap Antenna Pitch Plane Pattern...................1514. Haigh Half-Wrap Antenna Roll Plane Pattern..................1615. Ball Brothers Wrap-Around Antenna..........................1716. VSWR/Return Loss of Ball Brothers Antenna....................1717. Ball Brothers Antenna Yaw Plane Pattern.......................1818. Ball Brothers Antenna Pitch Plane Pattern.....................1919. Litton Wrap-Around Antenna..............................2020. VSWR/Return Loss of Litton Antenna.......................2021. Litton Antenna Yaw Plane Pattern.............................2122. Litton Antenna Pitch Plane Pattern.......................2223. NWCC Wrap-Around Microstripline Antenna.......................2324. VSWR/Return Loss of NWC Corona Antenna.....................2325. NWCC Antcnna Yaw; Plane Pattern.......................2426. NWCC Antenna Pitch Plane Pattern..........................25

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NWC TP 5099

ACKNOWLEDGMENT

Much of the information presented in this report was compiled through the

combined efforts of J. J. Allen and R. E. Rockwell in a preliminary

report published as Technical Note 3060-68-04, da t ed September 1968.

iv

NWC TP 5099

INTRODUCTION 4

Since early 1966, as a result of the planned conversion from VHF to UHFoperation on Navy test ranges, the Naval Weapons Center has been engaged in a Iprogram for the development of airborne antennas that would operate in thenewly assigned 1435-1535 MHz and 2200-2300 MHz UHF telemetry bands. Thisrequired a new concept in airborne telemetry antenna design, in answer to whichNWC personnel at China Lake and Corona* originated the concept of a wrap-around belt type antenna that could be used on almost all missile configurations.

Subsequently, a contract was let to the AVCO Corporation for the develop-ment of a wrap-around antenna using stripline techniques, under the direction ofWilliam Haigh. Mr. Haigh later formed his own company and, since the wrap-around stripline antennas are now being produced by Haigh As3ociates, this de-sign is referred to as the Haigh antenna. Antenna development contracts werealso awarded to Litton Systems and the Ball Brothers Research Corporationwhile in-house development continued at Corona.

Different design approaches were taken by the several developers. TheHaigh antenna uses a stripline design, the Ball Brothers and Corona antennas

use a microstr'pline design, and the Litton antenna is a dielectrically loadedwaveguide with crossed slots along the wall edge. Line drawings of the differentdesigns are shown in Fig. 1 and 2.

STRIPLINE AND MICROSTRIPLINE DESIGN

Figure 1 depicts both the stripline and microstripline designs of a wrap-around antenna. In the stripline configuration, representing the Haigh antenna,the center conductor is shown surrounded by a homogeneous dielectric mediumstructured between two ground planes. The microstripline configuration, rep-resenting the Ball Brothers antenna, has one ground plane and the center con-ductor is partially surrounded by a dielectric medium. If the top of the micro-strip conductor were co ,ered with a dielectric medium, we would then have theconfiguration of the NWC Corona design. Design equations are somewhat mod-ified from one configuration to the other.

The Corona personnel involved have since transferred to the Naval Missile Center, Point Mugu

(Code 5370).

1E

NWC TP 5099

CROSSED-SLOT DESIGN

Figure 2 depicts the crossed-slot design of the Litton antenna. The crossedslots, which are used as radiating elements in the broad wall of the waveguide,are excited by traveling waves within the waveguide. The pattern quality ob-tained with this design was poor; therefore, it is not recommended for airborneapplications unless improvements can be made that will optimize antenna per-formance.

ANTENNA-PATTERNMEASUREMENTPROCEDURE

The patterns of the different antennas were measured at the NWC micro-wave anechoic chamber at China Lake, with the test antenna mounted on adummy missile airframe. The missile coordinate system is shown in Fig. 3;the test setup for antenna-pattern recording is shown in Fig. 4.

This report presents typical VSWR plots and antenna patterns obtained dur-ing the evaluation tests and summarizes the progress of wrap-around antennadevelopment.

2

NWC TP 5099

SUMMARY OF TEST RESULTS

In addition to the wrap-around antennas discussed, blade antennas and othertypes that protrude from the missile skin were investigated during this evalua-tion program. However, for aerodynamic characteristics and missile handling,the wrap-arorod belt type has proved to be the most effective design that can beadapted to most missile configurations. The evaluation has established that the

Haigh, Ball Brothers, and Corona versions of the wrap-around system are allacceptable for the intended use. The Litton crossed-slot design did not meetperformance specifications. However, with further study, this version couldpossibly be improved to operate at a proper level of performance.

The approved antennas will handle RF power inputs of 20 watts under ex-

treme environmental conditions, such as altitudes of 100K feet and temperaturesof -55°C to +125°C. The Haigh antenna has withstood the environment of anactual missile firing with no loss of telemetry data. A VSWR of 2:1 is satisfac-tory, and antenna gain of -5 dB is nominal for these antennas, all of which canbe designed for both L and S band frequencies and constructed with thicknessesof 1/16-inch and 1/8-inch and widths to a minimum of three inches.

Brief descriptions of the wrap-around antennas evaluated are presented in

the following paragraphs.

IIAIGH ANTENNA

The Haigh antenna, which comprises a stripline eight-slot array (Fig. 5),was the first of the wrap-around type to be developed. This system, which hasproved to be very successful, is designed to fit almost all missiles of varyingdiameters, such as 5, 8, and 10 inches, and can be flush-mounted on the mis-sile skin. Its development has progressed so that it can also be designed foruse at frequencies outside the UHF telemetry bands. The antenna is horizon-tally polarized, and the radiation pattern is omnidirectional. Figure 6 showsthe system mounted on the telemetry section of a Shrike missile.

A plot of typical VSWR data obtained with the Haigh antenna is shown inFig. 7, and typical antenna patterns, measured using a mockup of a typicalmissile configuration, are shown in Fig. 8 and 9. The average antenna gain,referenced to isotropic as shown in Fig. 8, is about -4. 5 dB.

Several captive flight tests, during which the aircraft simulat d typicalmissile-launch maneuvers, were also conducted to demonstrate the trackingcapability of a ground-based auto-track antenna. Good signal strength was re-Cgived from thc The Haigh was also used for an

actual Shrike missile firing. Data reception, using a ground-based auto-trackantenna was 100% to missile impact. ii

3i

NWC TP 5099

Another version of the Haigh antenna is in use on a 10-inch diameter in-strumentation pod. This antenna (Fig. 10) is a half-wrap version of the sameconfiguration as the full wrap-around belt type antenna. Two half-wrap anten-nas--one for a frequency of 1700-1800 MHz, and the other for a frequency of2200-2300 MHz--were designed specifically for captive flight tests in wshich theantenna radiation pattern need only be in the lower hemisphere.

A plot of half-wrap antenna VSWR data is shown in Fig. 11; antenna patternsare shown in Fig. 12 through 14.

BALL BROTHERS ANTENNA

The antenna designed by the Ball Brothers Research Corporation uses micro-strip techniques for feeding the radiating elements (Fig. 15). It is a wrap-around type and has the same physical shape as that of the Haigh system. TheBall Brothers system has been used on missiles of various diameters and canalso be designed for operation at frequencies outside the UHF telemetry band.The antenna is polarized horizontally; the radiation pattern is omnidirectional.

A plot of VSWR data for this antenna is shown in Fig. 16; antenna patternsare shown in Fig. 17 and 18. The average antenna gain, referenced to isotropicas shown in Fig. 17, is about -5 dB.

This antenna is satisfactory for airborne use and is presently being im-proved so that the radiation pattern will be more omnidirectional.

LITTON ANTENNA

The Litton system (Fig. 19) is a dielectrically loaded waveguide formed inthe same shape as the Haigh and Ball Brothers systems. It is fed by a coaxialline with a TNC connector, and ti: - radiating elements are crossed slots in thebroad wall of the waveguide. The cr,.sed slots are excited by traveling waveswithin the waveguide. The antenna is circularly polarized and the radiationpattern is omnidirectional in the azimuth plane.

Since the VSWR data (Fig. 20) and the antenna patterns produced by thecrossed-slot system (Fig. 21 and 22) were not satisfactory, antenna gain wasnot measured.

Although Litton intended to develop an improved version of the crossed-slot design, no further work has been done to date, and the antenna in its pres-ent design is not recommended for airborne applications.

4

NWC TP 5099

NWC CORONA (NWCC) ANTENNA

The wrap-around antenna developed at NWC Corona (Fig. 23) uses micro-

strip techniques similar to those used in the Ball Brothers antenna and hasessentially the same physical shape. The circuitry is not visible in the figuresince it is covered with a dielectric material. In .iicrostrip circuits, air orsolid dielectric may be used on the side on which no ground plane exists. Theradiant field pattern of the antenna, which has four radiating elements and ishorizontally polarized, has better omnidirectional characteristics than the pre-viously discussed designs.

A plot of the VSWR data is shown in Fig. 24; antenna patterns, measured

on a dummy missile airframe, are shown in Fig. 25 and 26. The averageantenna gain, referenced to isotropic as shown in Fig. 25, is about -5. 0 dB.

CONCLUSIONS AND RECOMMENDATIONS

Of all the airborne antennas evaluated, the Haigh wrap-around belt-typesystem is the one in most general use at NWC at this time. This antenna isessentially universal in that the full wrap-around version has been used withsatisfactory results on the mockup missile configuration and in a flight testof the Shrike missile, and the half-wrap version is operating satisfactorily ona 10-inch instrumentation pod.

It is recommended that belt-type antennas be used for missiles of smalldiameter for the following reasons:

" Ease of missile handling, since there are no protrusions, which

also allows the missile to be tube-launched.

* No phasing harness or circuitry required inside the missile,allowing more room for other missile circuitry.

" Less aerodynamic disturbance since antenna can be flush-mounted to the missile skin.

" Has good omnidirectional pattern, which minimizes data lossregardless of attitude during launch and flight trajectories.

* Ease of installation and interchangeability for different fre-quency operation.

* Relatively low cost in quantities, and availability from two ormore sources.

5l

NWC TP 5099

* Not limited for use in the UHF telemetry band.

* Antenna is presently being used successfully on several types ofmissiles.

Further information can be obtained by writing to Commander, Naval Weap-ons Center (Code 306), China Lake, California 93555.

6

____ NWC TP 5099

loe loGround plane

Conductor

SGround plane

Stripline Microstrip Line

FIG. 1. Comparison of Stripline and Microstripline Configurations

Crossed slot

'-..Waveguide

wall

Dielectric

FIG. 2. Crossed Slot in the Broad Wall of a Dielectric LLoaded Waveguide.

7

NWC TP 5099

zI

Pitch Plane Yaw Plane (8)

\ E9

27 0 :90

Roll Plane C*)

FIG. 3. Missile Coordinate System.

Test Holding fixtureTransmitting antennahorn

[- ~O O-n IPoo T Airframe

Couplermer

RG-9/LJTWT 1 watt

Signal Receiver

FIG. 4. Test Setup for Pattern Measurements of Wrap-Around Antennas.

8

NWC TP 5099

-~~ LHL 134971 IFIG. S. Haigh Wrap-Around Antenna.

0J

LHL 134197

FIG. 6. Haighk Antenna Installed on TMSection of Shrike Missile.

9A

NWC TP 5099

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NWC TP 5099

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Haigh AntennaSeptember 17, 1970Freq. 2210 Os 90

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FIG. 8. Haigh Wrap-Around Antenna Yaw Plane Pattern.

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NWC TP 5099

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129

NWC TP 5099

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FIG. 10. Haigh Half-Wrap Antenna.

LHL 153904

VSWR Return loss. dB

1 43 -15

122 .20

1 12 -25

107 - 30

2200 2250 23D0Freqauency, MHz

FIG. 11. VSWR/Returs Loss of Half-Wrap Antenna.A

13

NWC TP 5099

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Haigh AntennaDecember 16, 1970

_ _ _q. 27000 900

FIG. 12. Haigh Half-Wrap Antenna Yaw Plane Pattern.

14

________NWC TP 5099

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NWC TP 5099

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NWC TP 5099

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FIG. 15. Ball Brothers Wrap-Arouind Antenna

VSWR Return loss, dB

193 -10

1.22 -20

1.07 -30

1470 Frequency, MHz 1490 1515

FIG. 16. VSWR/Return Loss of Ball Brothers Antenna.

17

NWC TP 5099

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NWC TP 5099

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NWC TP 5099

FIG. 19. Litton Wrap-Around Antenna.

VSWR Return loss, dB

OD 0

7.00- -2.5

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1.92 0.

2200 ~2250 20

Frequency, MHz II

FIG. 20. VSWR/Return Loss of Litton Antenna.

20

NWC TP 5099

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NWC TP 5099

FIG. 23. NWCC Wrap.-Around

Microstripline Antenna.

LHL 152380

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FIG. 24. VSWR/Retuni Loss of NWC Corona Antenna.

23

NWC TP 5099 _________ _____

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NWC TP 5099

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UNCLASSIFIEDSecurity Classification

DOCUMENT CONTROL DATA.- R & DSet irify rla, iitcauion of title, body of ab..ttart and indexing3 *nnotaounf naust be entered vvhen the overall report is ra-6.stledi

I OR1IINATING ACTIVITY (Corporate Authort) 2a. REPORT SECURI TV CLASSIFICATION

Naval Weapons Center UNCLASSIFIEDChina Lake, California 935S5 2b. GROUP

3 REPORT TITLE

EVALUATION OF AIRBORNE TELEMETRY ANTENNAS FOR USE IN UHF TELEMETRY BANDS

4. (DESCRIPTIVE NOTES (Type of report and tincluitve dates)

5 AUTHORMS (First ,ame, middle initial, last name)

V. R. Christenson

0. REPORT DATE 70. TOTAL NO. OF PACE lb or REFS

January 1971 ___ 268a. CONTRACT OR GRANT NO 9a. ORIGINATOR'S REPORT NUMSERIS?

b. PROJECT NO. NWC TP S099

AirTask AOS-53S-222/216-1/F99-05-01 Sb OIIR EPORT NOIS) (Any other numbers that may be assignedthsreot

d.

I0 DISTRIBUTION STATEMENT___________________________I

This~ ~ ~ ~ ~ ~ ~ ~~~~~aa Matmets t o~a xoftsadi.A0Win oera Comand

Naval aStems Command

Washington, D.C. 20360

ABSTRACT. Thlsfreport documents the results of a program conductedto evaluate experimental and commercially available UHF airborneantennas foruse in the 1435-1535 and 2200-2300 MHz telemetry bands.The evaluation established t hat a wrap-arounid type antenna givessatisfactory performance and is adaptable for use in several differentmissile configurations. The design and operational characteristics ofeach antenna evaluated in a missile configuration are presented, to-gether with typical antenna patterns and VSWR data obtained duringthe program.,

DD , NOV61 4 7 3 (PG )UNCLASSIFIED

S/N 0101-807-6801 Securltv Classification

UNCLASIlESecurity Classificaion________

14. LINK A LINKS8 LINK CKYWRSROLE: WT ROLE WT ROLE WT

Missile antennas

Wra p-arotund antennasIAntennat design

3OR (BACK) - _ _ _

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