Title :
A dual-channel cooled GaAsFET receiver for the Dominion Radio Astrophysical Observatory 26-metre radio telescope covering 1.35 to 1.75 GHz
Author :
Walker, G. ; Vaneldik, J.F. ; Routledge, D. ; Landecker, Thomas L. ; Galt, J.A.
Author_Institution :
Dept. of Electr. Eng., Alberta Univ., Edmonton, Alta., Canada
Abstract :
A low-noise receiver for a radio telescope is described. Two identical three-stage GaAsFET amplifiers were built which give excess noise temperatures of less than 28 K with at least 34 dB gain between 1.35 and 1.75 GHz when operated at a physical temperature of 12 K. This noise temperature is measured at the cryostat input connectors. The physical temperature is maintained by a closed cycle helium refrigerator. Source-inductance feedback is used to allow optimum noise performance combined with good input match. Return loss is better than 15 dB across the band. Construction details of the amplifiers and their mounting in the cryostat are provided. Sample observational results are presented.
Keywords :
III-V semiconductors; astronomical observatories; cryostats; field effect transistor circuits; gallium arsenide; radio receivers; radiotelescopes; solid-state microwave circuits; 1.35 to 1.75 GHz; 12 K; 15 dB; 26 m; 34 dB; 78 K; Dominion Radio Astrophysical Observatory; GaAs; He; III-V semiconductors; UHF; amplifiers; closed cycle helium refrigerator; cryostat input connectors; dual-channel cooled FET receiver; low-noise receiver; noise temperatures; physical temperature; radio telescope; return loss; source inductance feedback; Connectors; Extraterrestrial measurements; Gain; Noise; Receivers; Telescopes; Temperature measurement;
Journal_Title :
Electrical Engineering Journal, Canadian
DOI :
10.1109/CEEJ.1988.6592898
