Antenna DesignSenior Design, Fall 2011

Supervisors: Branislav Notaros, Olivera Notaros, Nada Sekeljic

Electrical Students: Nate Hufnagel, John James, Prabhat Lamsal

Mechanical Students: Steve Johnson, Robert Meyer

Antenna Design Team

Nate Hufnagel John James Prabhat LamsalSteve Johnson

•Electrical

•Team Leader

•Antenna Design

•Electrical

•Antenna Design

•Electrical

•Antenna Design

•Mechanical

•Antenna Fabrication

Project Goals

• Design, optimize and fabricate a family of horn

antennas, waveguides and coaxial to monopole

feeds that effectively cover the microwave

spectrum from 1 – 20 GHz

– Design and optimization was accomplished using WIPL-D

software

– Steve Johnson is currently fabricating our first two

standard gain horn antennas

Project Goals

• Produce antennas that are as good or better than

those already on the market

• Produce antennas at a fraction of the cost of those

already on the marketalready on the market

– Comparable standard gain horn antennas cost around

$700.00

– Our standard gain horn antenna cost $9.83 to produce

Standard Gain Horn Antenna Constraints

• Operate around 10 GHz

• Maintain 20 dB gain over the complete operational

frequency range

• Maintain a voltage standing wave ratio (VSWR) of less

than 2 over the complete operational frequency range

• Maintain a half power beamwidth (HPBW) that is less

than 20 degrees over the complete operational

frequency range

Why We Chose Horn Antennas

• Horn antennas have a directional radiation pattern

• Ability to achieve high gain

– Horn antennas have very little loss, so the gain of the antenna is nearly its directivity antenna is nearly its directivity

• Input impedance varies slowly over a wide frequency range

– Sufficient power will be delivered to the antenna

• Fabrication is somewhat simple and inexpensive

Simulation and Actual Results

• Conductivity

– We used perfect electric conductors (PEC) to model our antenna

– Our antenna is aluminum

• Antenna Excitation• Antenna Excitation

– WIPL-D models our feed as a simple delta pulse generator

– We will feed our antenna with 2.4 mm connector and coaxial cable

• This will lead to losses

WIPL-D Software

• 3-D Electromagnetic Solver

• Able to compute the radiation pattern of any antenna

• Parametrically sweeps multiple dimensions of Antenna for optimal

radiation

Our Antenna in WIPL-D

Constraints

• 20 dB gain over frequency range of 8-12 GHz

• VSWR to remain under 2 for 8-12 GHz

• HPBW (Half-Power Beam Width) of less than 20 degrees

VSWRVSWRVSWR stands for voltage standing wave ratio. It is a function of the reflection coefficient, which describes the power reflected from the antenna.

• Γ(gamma) is the reflection coefficient. The VSWR is always a real and positive number for the antennas.

• The smaller the VSWR is, the better the antenna is matched to the transmission line and more power delivered to the antenna. In our design we have VSWR of below 2 (1.97) over the frequency range of 8-12 GHZ.

VSWR (Final Dimensions)VSWR (Final Dimensions)

• VSWR remained below 2 for entire 8-12 GHz range

Gain (Final Dimensions)

• Gain over 8-12 GHz range

• Maintained over 20.66 dB reaching maximum of 23.32 dB

Phi Angle Cut for 10Ghz (HPBW)

• HPBW (Half Power Beam Width) of 10.24 degrees at 10GHz

• Shows Great Directivity

Final 3-D Radiation Plot (10 GHz)

•3-D Radiation Plot of Far-Field using WIPL-D

Testing TheTesting The AntennaAntenna

• After fabrication is complete , we are going to characterize our

antenna’s gain and VSWR using a Network Analyzer. This

operation is performed inside anechoic chamber to decrease

the noise and loss in the cables.

Source: Antenna radiation pattern[online]http://files.myopera.com/onyxluo/blog/scheme.jpg

ApplicationApplication

• The horn antenna is a particularly useful form of antenna for use

with RF(Radio Frequency) microwave applications, used in

defense weaponry and radar communication.

• There are two

antennas one for

receiving and one receiving and one

for transmitting

E.M waves , located

on the top of the

positioner control.

Source: CSU antenna test range 2009-

2010[online]http://www.engr.colostate.edu/ecedesign/AY09/antenna/Antenna_Test_Range_FA09.pdf

Budget EstimatesBudget EstimatesDescription Quantity Estimated price

1/32inch, 4 × 1 foot

Aluminum Sheet for

Antenna

1 $9.83

¼ inch,59 × 12 mm

Aluminum sheet for

Wave guide

2 Provided by Steve

Johnson(Mechanical

department)

2.4mm Female; 4 Hole

Panel Mount; .250

Extended Dielectric

2 $101.45

*Connecter will be fabricated in mechanical lab by Steve

Johnson. The status of the connecter is in progress. This will

cut down the cost of the antenna.Source: Pasternak enterprises [online]http://www.pasternack.com/product-2.4mm-Female-4-Hole-

Panel-Mount-.250-Extended-Dielectric-PE44218-70404.html

Cost Comparisons Cost Comparisons Standard Gain

Horn

Antenna

Fairview

microwave

Inc

Gain

(dB)

Freque

ncy

GHZ

3 dB

Beam

width

Body Cost

Connecter

Cost

Waveguide

Total

Cost

Antenna

QTY- 2 20 8.2 –

12.4

16.1° Alumi

num

$110 $90 $1792.8

Senior

Design

Team

Horn

Gain

(dB)

Frequen

cy GHZ

3 dB

Beam

Width

Body Cost

Connecter

Cost

Waveguide

Total

Cost

QTY- 2 20 8 - 12 11° Alumin

um

$202.90

Hopefully

zero

Zero $20

Source: Fairview microwave Inc

[online]http://www.fairviewmicrowave.com/Gain_horns.htm?gclid=CPTviO3d66wCFUHRKgodI0izJg

What’s Next What’s Next >>>>>>• Testing X-Band standard gain horn inside the Anechoic Chamber.

• Design & fabricate a broadband double-ridge horn antenna.

Anechoic chamber

• Test double-ridge horn in Anechoic Chamber with ATR team.

Source: Antenna anechoic

chamber[online]http://www.ee.calpoly.edu/media/images/projects/controller.jpg

Why go to Double-ridge??• Low VSWR(voltage standing wave ratio),less than 2.

• Broad band range 1-18 GHZ. So, we can use one single

antenna to cover the frequency range of 5 to 7 standard gain

horn.

• High gain over the wide range of frequency.

Source: Sunol science corporation[online]http://www.ramayes.com/_images/Sunol/Sunol_1-

18_GHz_Horn.jpg

Questions?