Werner Bächtold (Prof. em.) and Alexander Megej

Transcription

1 Werner Bächtold (Prof. em.) and Alexander Megej Laboratory for Electromagnetic Fields and Microwave Electronics, ETH Zürich Introduction: the HIFI-Receiver System The IF-2 Amplifier System The InP HEMT: a low noise microwave amplifier device Cryo-cooled amplifier From the (academic) prototype to the (industrial) flight model Conclusions Laboratory for Electromagnetic Fields and Microwave Electronics 1

2 IF-2: a part in the Herschel HIFI Receiver Chain 2

3 HIFI System Design: SRON Netherlands Institute for Space Research HIFI Dual IF System - one polarization (Identical diagram for the orthogonal polarization). 2 K level 4 K level 15 K level 290 K (SVM) mixer & isolator IF-1 amplifier level trimming IF-2 assembly cryoharness IF up-converter warm harness Spectrometers GHz IF 6H 6L IF gain: -1 db 29 db -3 db +30 db -6 db GHz -16 db -3 db -2 db 10.4 GHz GHz 5 HRS-V GHz IF IF gain: min. level: -1 db 25 db -128 dbm/mhz -5 db (+31 db) (-10 db) -108 dbm/mhz +21 db IF-2-Box: 14 amplifiers+ -8 db signal -85 dbm/mhzcombiners -95 dbm/mhz -3 db -2 db WBS-V -100 dbm/mhz 3

4 HIFI Receiver: Gain and Noise (Channel 1; GHz) 2 K 4 K 15 K 290 K Signal from Space Mixer Circulator IF-1 IF-2 Combiners Local Oscillator -80 dbm/mhz input Minimum Signal Level Mixer loss: 18 db IF-1 gain IF-2 gain Combiner loss kt O -140 Noise Temperature : T N = 100 K T N = 600 K 4

5 HIFI IF-2 Assembly - one polarization N. D. Whyborn, GHz IF +30 db Two amplifier types: 4-8 GHz IF Bands 1 5 (4 8 GHz) Bands 6H&L ( GHz) (+32 db) (-10 db) +22 db (Identical diagram for the orthogonal polarization) 5

6 Amplifier Specifications: Comment/Challenge Octave Bandwidths: (ultimate bandwidth and 4 8 GHz for hybrid technology) Power Gain: 32 db 0 (3 stage ampl.) Operation at T = 15K 0 (III/V devices requ.) Low noise temperature: < 50K 0 (HEMTs requ.) Input return loss: > 10 db, + (large bandwidth) Output return loss: > 10 db + (large bandwidth) Power dissipation 6 mw 0 (HEMTs requ.) +: challenging 0: manageable -: no problem) 6

7 Required semiconductor amplifier device: Low noise low power high gain - small input/output capacitance InP-HEMT (high electron mobility transistor) (World wide one space qualified device: TRW CRYO7) 7

8 InP HEMT: A Field-Effect Transistor for the mm- Wave Range InGaAs/InAlAs HEMT on InP Key Parameter: Gate-Length: 0.2 µm 0.1 µm. Max. Oscillation Frequency f max : 200 GHz 300 GHz InP Source Gate Drain Gate voltage controls electron current in GaInAs-channel from source to drain 8

9 HEMT Noise Properties The InP HEMT shows best microwave noise performance of all semiconductor devices. The HEMT noise sources are mostly thermal noise sources. the HEMT noise temperature scales with ambient temperature Typical: HEMT operating temperature 300 K 15 K HEMT noise temperature 60 K 6 K at f = 6 GHz Cryo-cooled InP HEMT microwave amplifiers are world champions in noise temperatures 9

10 Amplifier Design and Manufacturing: Hybrid technology (MIC) (Monolithic would be preferable no space qualified process available) Complex mounting and bonding technology for HEMTs, line elements, passive lumped devices 10

11 IF-2 Development Year ETH Industry Ampl. Predevelopment Final Design Manufacturing Delivery of IF-2 Flight Model (Oct. 2005) 11

12 Transfer to the Industry Prime Contractor, management product assurance, measurements: Mechanical construction: Electronics: Low temperature microwave measurements: Development of the amplifiers at the ETH prior to selection of the industrial partner no info available of space qualified mounting and bonding processes of the industry Significant and time consuming modifications and adaptations: Mounting and bonding processes for passive devices and HEMTs 12

13 IF-2 Amplifier Box 2 x 7 Inputs 2 x 7 Amplifiers Output combiner network 13

14 38 IF GHz Amplifier 28 Gain, G / db J106 J107 J113 J114 2,0 2,2 2,4 2,6 2,8 3,0 3,2 3,4 3,6 3,8 4,0 4,2 4,4 4,6 4,8 5,0 5, Noise Temperature (uncorr.), T n / K Frequency, f / GHz 14

15 Gain, G / db IF GHz Amplifier J101 J102 3,0 3,5 4,0 4,5 5,0 5,5 6,0 6,5 7,0 7,5 8,0 8,5J103 9,0 J104 J105 Frequency, f / GHz J108 J109 J110 J111 J Noise Temperature (uncorr.), T n / K

16 Summary of Measurements GHz Ampl. 4 8 GHz Ampl. Power Gain db Gain Ripple ± 1 ±1.2 db Input Reflection < -8 < -8 db Output Reflection < - 10 < -10 db Mean Noise Temp 13 (uncorrected) 17 (uncorrected) K Power Consumption <6 < 6 mw/ampl. 16

17 Conclusions A University Lab can design but cannot manufacture a space qualified device. The specifications for a system like HIFI are moving targets. The design takes longer (much longer) than expected. The cooperation with the industry was smooth, but required more time than expected. Our thanks go to 17