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Improvements in Microwave and Sub-mm Frontend Technology for Use up to 900GHz

Radiometer Physics GmbH (RPG), Germany. Improvements in Microwave and Sub-mm Frontend Technology for Use up to 900GHz. Harald Czekala RPG Thomas Rose RPG AchimWalber RPG Hugh Gibson RPG Oleg Cojocari ACST Byron Alderman STFC RAL. RPG Company Profile. Microwave, sub-mm, THz

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Improvements in Microwave and Sub-mm Frontend Technology for Use up to 900GHz

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  1. Radiometer Physics GmbH (RPG), Germany Improvements in Microwave and Sub-mm Frontend Technology for Use up to 900GHz Harald Czekala RPG Thomas Rose RPG AchimWalber RPGHugh Gibson RPG Oleg Cojocari ACST Byron Alderman STFC RAL

  2. RPG Company Profile Microwave, sub-mm, THz Turn-key radiometers, space technology components, design, scientific expertise ■ 4 decades experience ■ 40 employees ■ Radiometers (space) ■ Frontends/Receivers ■ Lab equipment / VNA ■ Components up to THz ■ Design+Manufacturing

  3. Outline: Receiver and Frontend technology at RPG • Direct detection (MMIC) for frequencies up to 120 GHz(LNA noise performance superior to heterodyne receivers) • Auto-calibration receivers up to 200 GHz(noise injection + magnetic Dicke switching) • At 118 GHz and up: sub-harmonic mixers (planar structures) • Improvements in mixer and multiplier designs throughclose cooperation with Schottky diode suppliers • Results of cooperation with Schottky technology suppliers • Schottky technology from ACST (Germany) • Schottky technology from RAL (UK) • Subharmonic mixers at 424 GHz and 664 GHz • InGaAS mixers with reduction of LO power by 10 dB

  4. Direct Detection 55 dB Pre-Amplifier Splitter and Filter Section Boosters and Detectors Video Amps, MUX, 16 Bit ADC Noise Injection Coupler 51- 59 GHz 7 Channel Filterbank Receiver Corrugated Feedhorn • Direct detection systems up to 110 GHz (since 8 years now…) • LNA mostly based on MMIC supply from IAF Freiburg, Germany • At 118 / 150 / 183 GHz and above, sub-harmonic mixers still have better performance (at least with high-quality sub-harmonic mixers) • Waveguide filters with high stability and narrow bandwidth (0.25 %) Compared to heterodyne systems: • Improved noise figure • Decreased long term stability (larger 1/f noise with InP MMICs) • Much better RFI protection • Compact (integrated) design • No planar filters, all waveguide

  5. Direct Detection: MMIC mounting • Mounting of all amplifier types • Experience in micromachining • Bonding and soldering to space standards

  6. Auto-Calibration Receivers • Noise injection calibration up to 200 GHz • 7.000 K signal at 183 GHz with stable noise diode (15 dB ENR) • Magnetically switched isolators:Dicke switching up to 150 GHz with low insertion loss (<=1.0 dB) • Fast switching with low currents (small thermal effects, 100 mA, 0.5 V) • Allan Variance Stability: 4.000 s • Less dependent on external calibration targets (LN2)!

  7. Auto-calibration receivers 90+150 GHz systems Achieved System Noise Temperatures: (incl. noise injection coupler, Dicke switch, isolator) 90 GHz: 750 K 150 GHz: 1200 K Full internal calibrationIsolation > 30 dB Insertion loss @ 90 GHz: 0.7 dB Insertion loss @ 150 GHz: 1.0 dB Allan Variance up to 4000 s

  8. Auto-calibration receivers 183 GHz system Heterodyne receiver at 183 GHzwith 6 channel Filterbank • Channel centers in IF: 0.6, 1.5, 2.5, 3.5, 5.0, 7.5 GHz • Noise injection for calibration • Tsys=1200 K for complete radiometer • Tsys=380 to 450 K for mixer • Schottky mixer diodeby ACST (Germany) Dome-C, Antarctica 3.300m asl, -25 to -80 °C Close to South-Pole Similar System on HAMP (HALO Microwave Package) for HALO research aircraft

  9. Schottky Mixer and Multiplier Improvements Anode pillar (contact pad) Air-bridge Membrane- substrate Mesa with anode Cathode pillar (contact pad) Back-side ohmic 25μm 50μm Air-bridges Mesas Membrane- substrate Protection pillars (contact pads) Back-side ohmic RAL Diode • Planar technology • Discrete Schottky devices • Semi-integrated and full integrated structures Two collaborations: • STFC/RAL, UK • ACST, Germany Mandatory improvements for 800 to 1000 GHz circuit mountings: • Reduced Cj0 • Reduced Cstr • Smaller size ACST Diode Quasi-vertical (QVD) single Diode (SD) Anti-parallel (APD) diode

  10. Vector Network Analyzer Products 50–75 GHz 60 – 90 GHz 75–110 GHz 90 – 140 GHz 110 – 170 GHz 140–220 GHz 220–325 GHz 325–500 GHz 500 – 750 GHz … OEM Network Analyzer Frequency Extenders for Rohde & Schwarz

  11. Tx/Rx Products • Transmit / Receive Systems: • 90 GHz, 183 GHz, 220 GHz, 324 GHz, 502 GHz, 640 GHz, 870 GHz • for compact ranges (antenna measurement facilities, phase + amplitude)

  12. RPG sub-harmonic mixers

  13. Receiver technology – 183 GHz example 183 GHz feeds and sub-harmonic mixers for ALMA-WVR • Best 183 GHz receivers available • Built in larger numbers • Noise-injection calibration @183(RPG only manufacturer world wide) • All ALMA water vapor radiometers equipped with RPG mixers and feeds

  14. RPG sub-harmonic mixers

  15. RPG Sub-Harmonic Mixer: 424 GHz LO Power: 5 mW Tmix=800 to 1200 K Conversion= –7 dB Tsys=1800 K

  16. Sub-Harmonic Mixer: 664 GHz LO Power: 3 mW Tmix ≈ 1600 K Conversion: –7.5 to –9.5 dB

  17. Further Schottky Diode Optimization: InGaAs Only at ACST: InGaAs Diode • InGaAs built-in voltage (barrier height) significantly lower than GaAs • (0.2eV compared to 0.8eV) • Reduced LO power required for SHM at 183 GHz: 0.34 mW (10 dB less!) 183 GHz InGaAs mixer with 0.2 / 0.25 / 0.34 mW LO-power

  18. Frontends and sub-systems for Space • Space qualified local oscillators (Herschel / ESA): • 8 local oscillator chains from 480 GHz to 1100 GHz • Other space projects: • EOS (NASA), ODIN (SSA), FIRST/HIFI, • MARFEQ, SAPHIR (CNES), MLS (NASA), FY-3 (China), …

  19. Space Products 2 • Space qualified front ends: • 183 GHz (4 channels) for sensitive water vapour detection • 90 GHz dual polarized receiver • 150 GHz dual polarized receiver

  20. Conclusion / Summary • Direct detection with superior performance (over heterodyne) up to 120 GHz (until better MMIC technology becomes available) • Auto-calibration schemes pushed to higher frequencies: • Noise injection up to 200 GHz • Magnetically switched isolators for high isolation, low loss (up to 150 GHz) • Development of improved sub-harmonic mixer series from 150 to 800 GHz Further steps: • Substrate Transfer • Film Diode Technology • Continuing reduction of capacities and size For further information: czekala@radiometer-physics.de www.radiometer-physics.de

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