Feed/Receiver Developments

ATA-TAP December 17, 2002

WJW

Prototype Wideband Feeds

0.5 – 11 GHz

Second Model H-Plane

Second Model E-Plane

Cross-Polarization Both Models

Gain Tables

Feed Tests

•Excellent (16 dB) matchExcellent (16 dB) match

•Agrees with EM calcs on

Impedance

Gain

Internal Loss

Measured LNA Temperature

Measured and simulatednoise for WBA13 at 300K,

77K and 4K

MMIC InP PHEMT .18 mDesign by S. Weinreb

Tip Circuit Board

Dewar Layout

Input Match and Cross Talk

Feed Properties

• Input impedance– <Zin>=206 Ohms

– Smax=1.35 Spillover

42o 18%

90o 8.5%

135o 3%

• Spillover

Odd Mode Resonances: No Cover

Odd Mode Resonances: w. Cover

Resonances w. & w/o. Cover: Absorber Added

Spillover vs. Zenith Angle

Zenith Angle

Tsy

s

Noise Summary for 10 GHzItem Temperature Notes

Feed (3%) 9.0 Const w freq

Tip Circuit Bd 3.0 Varies w freq

Transition Line 2.6 (20mil) Varies w freq

Cold Line 2.4 Varies w f req

Spillover 3.0 Const w freq

Tbb 2.7 Const

Atmosphere 7.0 4.0 @ 4GHz

LNA 12.0

Total 42.0 36.0 @ 4GHz