1. KFPA Noise Calibration Module and Coupler Eric W. Bryerton NRAO CDL (Charlottesville)

2. EVLA 18-26.5 GHz Receiver Thermal Gap Phase-Shifter RCP LNA Ortho-Mode Transducer Cal Coupler Cryo Isolator LCP LNA Cold Straps 15ºKelvin Cold Stage Stainless Steel Coax

3. Options for Cold Noise Calibration Source MMIC LNA Single HEMT GaAs Schottky Diode Tested 3 different K-Band MMIC LNAs Hittite HMC517, HMC519, and UMS CHA2092b Output Noise should be (Gain * Noise Temperature) Can we get enough noise with low power dissipation?

4. KFPA Cold Pixel OMT Noise Coupler Isolator LNA Phase Shifter Feed Dewar Top Plate Dewar Bottom Plate

5. KFPA Noise Cal Module Specifications RF In/Out: WR42, UG595/U Flange RF Channel Isolation: 40 dB Equivalent Injected Noise: 1.5-6.0 K Injected Noise Flatness: TBD (xxdB/yyMHz) Dissipated Power: 15 mW maximum to 15K stage Response Time: 100 us maximum rise/fall Stability: +/- 3% over 4 hours (TBC), TBD over 1 year NOT CAL: TTL Low -> Injected Noise ON

6. Noise Cal Test Block MMIC LNA

7. Noise Cal Test Block Measurements Measure P on /P off ratio, then:

8. Noise Cal Test Block Measurements LNA 20dB Atten Noise Cal Test Block

9. Noise Cal Test Block Measurements 8mA 10mA 11mA V DS =0.85V -> P DC =6.8mW for bottom trace

10. Added Noise Versus Cal Coupling Not including ohmic losses 25dB coupler adds about 0.05K more noise than 30dB coupler

11. Noise Cal Test Block Measurements

12. 22.25 GHz, Vds=0.85V, Vgs=-0.54V, Ids=10mA

13. Noise Cal Test Block Measurements +3% -3% 22.25 GHz, Vds=0.85V, Vgs=-0.54V, Ids=10mA 9:40am

14. Noise Cal Test Block Measurements +3% -3% 22.25 GHz, Vds=0.85V, Vgs=-0.54V, Ids=10mA 3:39pm

15. Noise Cal Test Block Measurements +3% -3% 22.25 GHz, Vds=0.85V, Vgs=-0.54V, Ids=10mA 7:20pm

16. Noise Cal Test Block Measurements To keep bias fluctuations from changing T cal more than 0.2%: V DS stable to within +/- 1 mV V DS stable to within +/- 10 uV (or, I DS stable to within +/- 5 uA)

17. 6-Port Bethe Coupler CST Simulations P1 P4 P6 P2 P3 P5 P1: noise source P2: load for uncoupled noise cal power P4->P3, P6->P5: main signal path (OMT->isolator)

18. 6-Port Bethe Coupler CST Simulations Coupling = -30.5 +/- 0.5 dB (S31, S51)

19. 6-Port Bethe Coupler CST Simulations Input Match (noise source and signal path) < -40 dB (S11, S44) Channel-to-Channel Isolation > 60 dB (S54) Directivity >20 dB (S31/S41)

20. Integrated Noise Cal/Coupler Block for Single Pixel Prototype Gold-plated aluminum block Coupling holes are 0.100” diameter