1. System Considerations for Submillimeter Receiver
Junji INATANI
Space Utilization Research Program
National Space Development Agency of Japan
(NASDA)
March 12-13, Nanjing

2. Introduction 640 GHz SIS Receiver for SMILES System Considerations:
Superconducting Submillimeter-wave Limb-emission Sounder
System Considerations:
System Noise Temperature
Sideband Separation
Main Beam Efficiency
Standing Waves
Gain Stability
Spectral Resolution
Electromagnetic Interference (EMI)
March 12-13, Nanjing

3. March 12-13, Nanjing

4. Japanese Experiment Module “KIBO”
SMILES
March 12-13, Nanjing

5. View inside the Cryostat
Instruments
SMILES:
Superconducting Submillimeter-wave Limb-emission Sounder
View inside the Cryostat
March 12-13, Nanjing

6. Signal Flow
March 12-13, Nanjing

7. Inside the SIS Mixer Mount Developed by NASDA in-house activity.
640 GHz SIS Mixer
Inside the SIS Mixer Mount
Developed by NASDA in-house activity.
0.4 mm
Nb/AlOx/Nb Mixer Device
Fabricated at NAOJ, Nobeyama
March 12-13, Nanjing

8. Cooled HEMT Amplifiers
20K-stage Amplifier
100K-stage　Amplifier
Tphys = 300K
Vd = 2V, Id = 10mA
Tphys = 300K
Vd = 2V, Id = 10mA
Tphys = 20K
Vd = 1V, Id = 5mA
Tphys = 100K
Vd = 1V, Id = 5mA
Two HEMT Devices: FHX76LP
Gain:
23-26
Three HEMT Devices: FHX76LP
Gain:
30-33
Nitsuki Ltd.
March 12-13, Nanjing

9. Cryostat Radiation Shield: MLI (40 layers)
Signal Input Window: IR Filters (‘Zitex’)
Support for 100 K Stage: S2-GFRP Straps (12 pieces)
Support for 20 K Stage: GFRP Pipes (4 pieces)
Support for 4 K Stage: CFRP Pipes (4 pieces)
March 12-13, Nanjing

10. 4 K Mechanical Cooler Cooling to 100 K & 20 K:
Cooling Capacity:
20 mW @ 4.5 K K K
Power Consumption:
300 W @ 120 VDC
Mass:
Cooler 40 kg
Cryostat 26 kg
Electronics 24 kg
Total 90 kg
Cooling to 100 K & 20 K:
Two-stage Stirling Cooler
Cooling to 4.5 K:
Joule-Thomson Cooler
March 12-13, Nanjing

11. Mechanical Components of Coolers
Cold-head and Compressor for Two-stage Stirling Cooler
Two Compressors for Joule-Thomson Cooler
March 12-13, Nanjing

12. Thermal Design of Cryostat
Window: Heat flow is reduced with two IR filters
IF cables: CuNi coaxial cables
HEMT current: Circuit is optimized for a Starved Bias Condition
JT load: Minimized by reducing the rate of GHe flow
March 12-13, Nanjing

13. Sub-mm Receiver Subsystem
To Antenna
Ambient Temperature Optics
AOPT
Cryostat
To Cold-Sky
Terminator
AAMP
Single Sideband
Filter
CREC
Sub-mm
LO Source
He Compressor (JT)
He Compressor (ST)
March 12-13, Nanjing

14. Acousto-Optical Spectrometer
Bandwidth:
1200 MHz x 2 units
IF: GHz / unit
Focal Plane:
1728-ch. CCD array x 2 units
Frequency Resolution:
1.8 MHz (FWHM)
Channel Separation: 0.8 MHz / ch.
AD Conversion:
12-bit, 2-CCD readouts
in 4.9 msec
Adder Output:
16 bits x 1728 ch. x 2 units
in 500 msec
AOS (Astrium & OPM)
March 12-13, Nanjing

15. System Considerations
System Noise Temperature
Sideband Separation
Main Beam Efficiency
Standing Waves
( Gain Stability )
( Spectral Resolution )
Electromagnetic Interference (EMI)
March 12-13, Nanjing

16. System Noise Temperature
Good mixer
Good IF amplifier
Low insertion loss in sub-mm optics
Tsys for SSB mode
March 12-13, Nanjing

17. Sideband Separation Martin-Pupplet Interferometer (RF filter)
One mixer for one sideband, one polarization
Two mixers for two sidebands, one polarization
Narrow RF bandwidth: mech. tunable or fixed
Phase Synthesis (Single-ended mixer)
Broad RF bandwidth: no mech. tuner necessary
Poor LO coupling
Phase Synthesis (Balanced mixer)
Four mixers for two sidebands, one polarization
Efficient LO coupling
March 12-13, Nanjing

18. Single Sideband Filter
FSP
Mechanically fixed filter
No standing waves
March 12-13, Nanjing

19. SSB Balanced Mixer
March 12-13, Nanjing

20. Main Beam Efficiency Low Spill-over for Main and Sub- Reflectors
Use of Primary Horn’s Optical Image
No electric field outside the horn’s aperture
It is the case for its optical image, ideally
Field distribution is independent of frequency
Relation of Horn Aperture and Its Optical Image
March 12-13, Nanjing

21. Method of Optical Image
March 12-13, Nanjing

22. Optical Image: characteristics
Wavefront is frequency independent  Broad-band design
Wavefront is scaled from the original one  High beam-efficiency
March 12-13, Nanjing

23. Standing Waves: a simple model
March 12-13, Nanjing

24. Comparison of Three Absorbers
Baselines
@ 625 GHz
Return 625 GHz
A. Murk (Univ. Bern) &
R. Wylde (TK)
March 12-13, Nanjing

25. Standing Waves: sensitivity limit (SMILES)
March 12-13, Nanjing

26. Expected Sensitivity
March 12-13, Nanjing

27. Accuracy of Absolute Brightness Temp.
March 12-13, Nanjing

28. ISS Environmental Fields
March 12-13, Nanjing

29. Cutoff Filter
March 12-13, Nanjing

30. Reflection of BBH RX BBH TX @ 625 GHz A. Murk, Univ. Bern R. Wylde, TK
March 12-13, Nanjing

31. Conclusions 640 GHz SIS Receiver for SMILES System Considerations:
Superconducting Submillimeter-wave Limb-emission Sounder
System Considerations:
System Noise Temperature
Sideband Separation
Main Beam Efficiency
Standing Waves
Gain Stability
Spectral Resolution
Electromagnetic Interference (EMI)
March 12-13, Nanjing