Cooling a low noise amplifier with a micromachined cryogenic cooler

Abstract

The sensitivity of antenna systems increases with increasing active area, but decreases at higher noise figure of the low-noise amplifier (LNA). Cooling the LNA locally results in significant improvement in the gain and in lowering the noise figure of the LNA. Micromachined Joule-Thomson (JT) coolers can provide a cryogenic environment to the LNA. They are attractive because they have no cold moving parts and can be scaled down to match the size and the power consumption of LNAs. The performance of a LNA mounted on a JT microcooler with dimensions of 60.0 × 9.5 × 0.72 mm(3) is reported in this paper. The microcooler is operated with nitrogen gas and the cold-end temperature is controlled at 115 K. The measured net cooling power of the microcooler is about 43 mW when the LNA is not operating. The power dissipation of the LNA is 26 mW, with a supply voltage of 2 V. At room temperature the noise figure of the LNA is 0.83 dB and the gain lies between 17.9 and 13.1 dB, in the frequency range of 0.65 and 1.05 GHz. Upon cooling to 115 K, the noise figure drops to 0.50 dB and the increase in gain varies in the range of 0.6-1.5 dB.

Laser cooling in solids: advances and prospects

“…This reduction in the size and mass of an antenna can be especially important in fasttracking systems, which require antennas to slew rapidly. Recent experiments have shown that cooling the LNA to 115 K can allow the antenna area to be reduced by about 43% [162].…”

Progress in and Outlook for Cryogenic Microcooling

“…The application potentials of a microcooler coupled with electronic devices has been demonstrated by cooling an yttrium barium copper oxide film through its superconducting phase transition by using a 30 K two-stage microcooler [100]. The utilization of the microcooler in cooling a low noise amplifier (LNA) was investigated by using a 115 K single-stage microcooler [101]. The performance of an antenna system can be improved by cooling the LNA stage in order to reduce its noise figure.…”

Expanding the field of view: station design for the AAMID SKA radio telescope

“…Alternatively to large cryogenic Helium coolers, like GM or Stirling coolers, Nitrogen micro coolers have been developed [99]. In this concept high pressure Nitrogen (80-120 bar) flows through micro channels in a Silicon substrate before expanding in the tip, cooling that area, and being transported back to a separate compressor.…”