1. IF1 CDR 9/12/031 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) IF-1 high (4-8 GHz) design and DM results Carmen Diez, Isaac López-Fernández, Juan Daniel Gallego, Alberto Barcia, Pere Planesas Centro Astronómico de Yebes Observatorio Astronómico Nacional Apartado 148, 19080 Guadalajara, SPAIN

2. IF1 CDR 9/12/032 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Contents n IF 1 (4-8 GHz) Specification n IF 1 (4-8 GHz) Design and DM results l Design choices l Results from DMs n Experience with IF 1 (4-8 GHz) DMs l Operational experience l Overview of IF 1 problems and failures l Discussion

3. IF1 CDR 9/12/033 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) SPECIFICATION (introduction)

4. IF1 CDR 9/12/034 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) SPECIFICATION (performance) n Frequency Band: 4-8 GHz n Noise Temperature: 10 K (baseline), 5 K (goal) n Gain: >22 dB n Gain ripple: ±2dB (baseline), ±1.5dB (goal) n Input Return Loss: < 0dB (no isolator) n Output Return Loss: <-10 dB (baseline), <-15 dB (goal) n Stability: K>1 (all frequencies) n Maximum Power Dissipation: 5 mW Bias Range: 0<Vd<1V, 0<Id<5mA, –11.0V<Vg<5.9V Normalized Gain Fluctuation @ 1 Hz: 3 × 10 -4 (Hz )-1/2 (baseline), 1.4 × 10 -4 (Hz )-1/2 (goal)

5. IF1 CDR 9/12/035 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) SPECIFICATION (interfaces) n Envelope: 78  45.3  15 mm n Mounting holes: 3 Helicoil M2.5 n Interface surface: gold plated, 10  m flatness n RF connectors: SMA (4 screw for O-ribbon) n DC connectors: MDM (9 pin P type, no gasket) n DC pin allocation: includes Ground sense n DC pin allocation: pins not used are grounded

6. IF1 CDR 9/12/036 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) SPECIFICATION (interfaces) n Bias circuit l Gate voltage divider l ESD protection l EMC rejection

7. IF1 CDR 9/12/037 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) SPECIFICATION (environmental) n EMI/ESD: provision of an additional cavity (not used) l EMI tests performed on DMs l ESD tests done in HEMTs n Radiation: tests done at KOSMA on InP HEMTs n Thermal Cycles: 50, RT to Cryogenic n Bake-out: 5, RT to 90 C n Vibration l Qualification at 90 K l Acceptance at RT, reduced level n Vent holes

8. IF1 CDR 9/12/038 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN (history 1) n Goal 1: 4 GHz Bandwith l Center frequency 10 GHz: è Less fractional BW è Isolators available è Bad for HEB l Center frequency 6 GHz: è More fractional BW è Isolators needed development è Possible for HEB n Goal 2: Low Power Dissipation l GaAs: Commercial, well established, initially considered l InP: Experimental, qualification needed, lower noise and power

9. IF1 CDR 9/12/039 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN (history 2) YXF 8-12 GHzYCF 2000 (Mixer Groups) YCF 5000YCF 6000

10. IF1 CDR 9/12/0310 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN (history 3) n 37 4-8 GHz YCF amplifiers fabricated at CAY in different series n All processed performed in our labs n Design transferred to Alcatel Espacio to build Flight Models n Series analyzed here: l YCF 2 – ETH transistors (Mixer Program Amplifiers) l YCF 6 – TRW transistors (Development Models)

11. IF1 CDR 9/12/0311 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Design Description (1) Interstage matching circuits MICROTECH DC connector SMA connector Bias cavity with biasing circuits Transistor area detail. See source inductive feedback and drain resistive loading ETH transistor with bonding wires 1 23 Input matching circuit Output matching circuit

12. IF1 CDR 9/12/0312 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Design Description (2) n Microstrip hybrid design simulated by MMICAD software n Developed cryogenic models for transistors, connectors, critical capacitors, resistors and bonding wires n Each InP device is independently stabilized by resistive loading and inductive feedback n Input matching circuit for optimum noise n Tuning elements incorporated in the design (adjustable bonding wires, microstrip islands) n Box resonances avoided with careful EM design and the use of microwave absorbers n Multiple bias networks requirements must filter RF, è Contribute to the unconditional stability of the amplifier è Comply with EMC mission requirements è Provide ESD protection of sensitive InP HEMTs è Have a low drain voltage drop

13. IF1 CDR 9/12/0313 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Design Description: Reliability n Reliability is a priority over performance for the selection of components, substrates and mounting techniques è Spatial design è Cryogenic operation n Past experience in cryogenic designs obviates most of the work in testing, modeling and pre-qualifying components n An example: ‘O’ ribbon connection in the SMA tab contact: l Allows mobility in three axis l Excellent electrical properties compared with traditional SMA connections

14. IF1 CDR 9/12/0314 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN: Cryo Capacitors

15. IF1 CDR 9/12/0315 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN: Measurement of cryogenic S parameters

16. IF1 CDR 9/12/0316 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN: Measured S parameters of a InP HEMT

17. IF1 CDR 9/12/0317 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN: Experience with HEMTs (2) n Wide experience with HEMT devices l More than 30 batches of commercial GaAs transistors tested l Several models of InP transistors measured è JPL-TRW (CHOP program): 15 batches, 9 models è ETH Zurich: 8 batches, 4 models è Chalmers University: 1 batch è HRL: 1 Batch

18. IF1 CDR 9/12/0318 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN: InP HEMTs ETH T-35  200×0.2 μm gate  Experimental transistor  Design by request  Used in DMs TRW T-45 CRYO4  200×0.1 μm gate  Used in DMs  Space qualifiable, to be used in FMs  CHOP developed TRW T-42 CRYO3  200×0.1 μm gate  Best performance 0.22 mm 0.19 mm

19. IF1 CDR 9/12/0319 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DESIGN: Closed Cycle Cryostat

20. IF1 CDR 9/12/0320 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Performance: Noise and Gain Measurement procedures n Measurement procedure: cold attenuator n Two measurement systems available at our labs: l System 350: è Older è More pessimistic è Used to keep traceability with past measurements è All noise tests shown here were performed with 350. l System 1020: è Newer calibration. è Gives 0.75 K better results n Estimated error (both) 1.4 K (repetitivity < 0.2 K)

21. IF1 CDR 9/12/0321 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) MP amplifier YCF 2  2 stages ETH 200 µm  Gold plated brass  61.4×35×11.5 mm, 149 g  Duroid 6002 substrates DM amplifier YCF 6  2 stages TRW 200 µm  Gold plated aluminum  58×32×15 mm, 65 g  Duroid 6002 substrates  Improved bias circuits  Additional cavity for filtering

22. IF1 CDR 9/12/0322 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Performance: Noise and Gain Results

23. IF1 CDR 9/12/0323 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Performance: Reflection and Stability n Worst case output reflection l Average DMs:-14.3 dB l Average MPAs:-13.0 dB n Model prediction of output return losses needs refinement n Isolator at the input (not designed for low input ref.) n Unconditionally stability for most bias points checked with sliding shorts

24. IF1 CDR 9/12/0324 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Performance: Gain fluctuations Correlation with voltage fluctuations n Fluctuations of gate voltage measured with HP35670A n Moderate correlation with gain fluctuations for different amplifiers measured at the same bias point n This simple DC measurements may be useful for pre-selecting least fluctuating devices from a batch 1 Hz

25. IF1 CDR 9/12/0325 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Performance: Gain fluctuations Bias dependence n Tested the variation of gain and voltage fluctuations with drain voltage l Found a steep change in gain voltage around 0.5 V l The behavior of gain and voltage fluctuations is similar as Vd varies n High fluctuation zones could be avoided with no penalty in noise or gain n Voltage fluctuations may help detecting these bias regions

26. IF1 CDR 9/12/0326 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DM Program (Yebes) HIFI YCF 6000 (Results)

27. IF1 CDR 9/12/0327 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Performance: Isolators Impact in overall performance n Isolators measured @ 14 K (PAMTECH gives data @ 77 K) n Good agreement between measurement (one case) and estimation of isolator noise: n Mean contribution 1.1 – 1.4 K

28. IF1 CDR 9/12/0328 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Performance: Isolators Results

29. IF1 CDR 9/12/0329 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) DM Program (Yebes) HIFI YCF 6004

30. IF1 CDR 9/12/0330 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) QM & FM PROGRAMS (ALCATEL) ALCATEL AEO 1 ALCATEL AEO 1

31. IF1 CDR 9/12/0331 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) QM & FM PROGRAMS (ALCATEL) ALCATEL AEO 1 ALCATEL AEO 1

32. IF1 CDR 9/12/0332 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Conclusions n 34 Cryogenic InP HEMT 4-8 GHz cryogenic amplifiers fabricated for HERSCHEL, including the Development Models with TRW transistors n Cryogenic S parameters of InP transistors measured in microstrip and noise models developed n Cryogenic isolators used at the input allow wide-band mixer- independent design with small penalty in noise n Exceptional performance and repeatability for the final DMs: 3.5 K noise and 27±1.1 dB gain dissipating 4 mW n Gain fluctuations exhibit a greater dispersion l Low frequency noise of gate bias may help selecting more stable devices n Acute sensitivity of gain fluctuations to bias point l Gate bias noise measurements could detect bias regions of high fluctuations

33. IF1 CDR 9/12/0333 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Experience with IF 1 DMs: FAILURES n Amplifiers YCF 6 (12 amps, 1 fail.) l Development models (5) è No failures è YCF 6006 presents anomalous gain fluctuations at room temperature l Mixer Groups (4) è YCF 6007 failure: Id1=0 @15 K was reported by SRON. This behavior could not be repeated in our labs even after 10 cooling cycles. è YCF 6012 failure: Id2=7 mA (uncontrolled) was reported by KOSMA. The transistor (IREL1) is broken. l Rest (3) è No failures

34. IF1 CDR 9/12/0334 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Experience with IF 1 DMs: FAILURES n Amplifiers YCF 2 (20 amps, 1 fail.) l Mixer Groups (8) è YCF 2006 failure: anomalous gate voltages and very high noise temperatures reported. In our labs we only detected certain hysteresis in the behavior of the 2 nd stage transistor (ETH) è YCF 2009 failure: high noise temperature reported. The amplifier was measured in our labs showing no anomalies. No action was taken l Rest (12) è No failures

35. IF1 CDR 9/12/0335 Centro Astronómico de Yebes, Obs. Astronómico Nacional, IGN (Spain) Conclusions n Failures: 2 in 32 amplifiers l ETH InP HEMT dead (ESD?) l TRW InP HEMT dead (ESD?) n No failures in other components, materials, and processes