1. Junji Inatani and SMILES Mission Team (NASDA & CRL)
EMC Design of SMILES
Junji Inatani
and
SMILES Mission Team
(NASDA & CRL)
July 25, 2001
JEM-SMILES

2. Contents Introduction to SMILES Particular EMC Required for SMILES
SMILES’ Strategy of EMC Design
Experimental Results
Conclusions
July 25, 2001
JEM-SMILES

3. July 25, 2001
JEM-SMILES

4. Instruments
SMILES:
Superconducting Submillimeter-wave Limb-emission Sounder
View in the Cryostat
July 25, 2001
JEM-SMILES

5. Signal Flow
July 25, 2001
JEM-SMILES

6. ISS Environmental Fields
July 25, 2001
JEM-SMILES

7. EMC Requirement of SMILES
All components shall work properly while SMILES meets the specified requirements
CE, RE, CS, RS SSP-30237
EMC at “malfunction” level
RS (radiation susceptibility) is most critical for SMILES to achieve its designed sensitivity
SMILES deals with atmospheric emissions at extremely low levels (completely passive sensor)
EMC at “spurious emission” level
EMC to deteriorate the linearity of detection
July 25, 2001
JEM-SMILES

8. SMILES’ Strategy for EMC Design
EM shielding with mainframe panels
To protect ambient temperature components
conductive seal, cutoff filter (venting holes)
EMC with PIU (connections to JEM-EF)
EM shielding with receiver cryostat
To protect cryogenic temperature components
conductive seal (metallic O-ring)
low-pass filter for DC input leads
EMC design in submillimeter optics
Immunity of components to be improved
To request control for GHz emissions
July 25, 2001
JEM-SMILES

9. Signal Level Diagram
July 25, 2001
JEM-SMILES

10. SMILES Structural Model
Antenna (REF)
Antenna (TRN)
Acoustic test was done to establish mechanical design.
EM shielding performance was measured.
Alignment Panel
Star Trackers
Calib. Hot Load
July 25, 2001
JEM-SMILES

11. Shielding Effect of Mainframe Panels
July 25, 2001
JEM-SMILES

12. Shielded Receiver Submm Optics (AOPT) Antenna Receiver Cryostat
Bellows
Back-to-back Horn
(Cutoff Filter)
SIS Mixer
4 K
20 K
HEMT Amp.
100 K
300 K
Receiver Cryostat
July 25, 2001
JEM-SMILES

13. Ambient Temp. Optics (AOPT)
To Antenna
AOPT
Cryostat
To Cold-Sky
Terminator
AAMP
Single Sideband
Filter
CREC
Sub-mm
LO Source
He Compressor (JT)
He Compressor (ST)
July 25, 2001
JEM-SMILES

14. Cutoff Filter (Circular Waveguide)
Mainframe/Venting Holes: D= 4.0 mm, L= 7.0 mm
Optics/BBH (Signal): D= mm (profiled), L= mm
Optics/BBH (Image): D= mm (straight), L= mm
July 25, 2001
JEM-SMILES

15. AOPT (EM) Signal/Image Coupler SSB Filter LO/Image Coupler LO Source
BBH (Image Port)
BBH (Signal Port)
July 25, 2001
JEM-SMILES

16. Reflection of BBH Return Loss > 50 dB RX BBH TX @ 625 GHz
A. Murk, Univ. Bern
R. Wylde, TK
July 25, 2001
JEM-SMILES

17. Conclusions
ISS Electro-magnetic environment is harmful to some type of experiments like SMILES.
To cope with that, SMILES has adopted two-fold EM shielding techniques for its sensitive instruments.
SMILES structural model has achieved the shielding performance above dB.
For SMILES to fully enjoy its sensitive observations, ISS environmental field has to be less than 2 V/m at GHz.
July 25, 2001
JEM-SMILES