Feed/Receiver Developments
ATA-TAP December 17, 2002
WJW
Cross-Polarization Both Models
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
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