ASIAA SMA - Sub-Millimeter Array, ASIAA SMA
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As the heart of the antenna, the superconducting receiver systems are being constructed in the receiver laboratory of the ASIAA. To achieve high sensitivity, several key components for the SMA receiver only exist in few research laboratories around the world, and none of the places is in our own lab prior to joining this project; to name a few: wide-band, high frequency local oscillators, wide-band multipliers at sub-millimeter wavelength, the low-noise C-band pre-amplifiers, and quasi-optics techniques.

One of the most critical processes for the SMA is to access the source of the SIS mixers. We have decided to build up our own expertise in mixer design, fabrication, and testing. The learning process has been jump-started by our partner in the SAO receiver lab. For SIS junction fabrication, it has been a collaborative effort between the ASIAA, the Material Science Center of National Tsing-Hua University (NTHU) in Taiwan, the Nobeyama Radio Observatory (NRO) of Japan, and Purple Mountain Observatory of China. Currently, the ASIAA mixers for the 200 GHz and 300 GHz bands have been installed in the antennas with very good performance. The mixer design and fabrication for the 600 GHz and higher is an on-going effort.

Summary For SMA Receiver System

Frequency Coverage 176-256 GHz
250-350 GHz
400-520 GHz
600-720 GHz
780-900 GHz
Number of receivers modules in a s ingle cryostat 8
Signal Detection / Detector Heterodyne / SIS Mixer (Nb-Al2O3-Nb)
Pre Amplifier (Operation Temperature) NRAO HEMT LNA Amplifier (4 K)
IF Frequency/Bandwidth 5GHz/2GHz
LO Source Gunn Oscillator / Multiplier
Operating Scheme Dual-Channel Operation
Refrigerator Closed-Cycle JT/GM Fridge
Cooling Power > 2.5W @ 4K


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