S/X Cryogenic Receiver Technology for VLBI Satellite Tracking

Abstract

The high sensitivity cryogenic receiver is the important equipment to improve the measurement accuracy of the satellite tracking for Chinese Lunar Exploration Project. The low noise amplifiers of front end are cooled to 15 Kelvin. The equivalent noise temperature of cryogenic receiver is one order of magnitude lower than the traditional equipment working at room temperature， greatly improving the sensitivity of radio telescope. Several advanced technologies have been adopted to simultaneously realize highly sensitive dual-band observations on the same target，including S/X dual-band feed horn，cryogenic low noise amplifier based on HEMT，cryogenic polarizer and low temperature superconducting filter. The measured receive noise of S-band is 8 K in the frequency range 2.19～2.3 GHz，and the system noise is 53 K at zenith. The measured receiver noise of X-band is 13 K in the frequency range 8.2～9.0 GHz，and the system noise temperature is 32 K at zenith. The S/X cryogenic receivers have been applied successfully for VLBI satellite tracking in Chinese Lunar Exploration Project.

Keywords

cryogenic receiver / polarizer / noise temperature / low noise amplifier