31 July 1998 Multibeam SIS mixer module for a focal plane array receiver
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Abstract
The integration of many receiver units into a receiver array is a common method of improvement of imaging systems. This approach, well known in the mm band for Schottky mixer arrays, has not so far been developed for Superconductor-Insulator- Superconductor (SIS) junction mixers, which give the best sensitivity in the short mm wave range and in the submm range. We demonstrate for the first time a practical low noise multibeam receiver module using SIS mixer technology. The module comprises three identical SIS mixers integrated with a common local oscillator, coupled through a three branch waveguide directional coupler. The multibeam module has been developed for a focal plane array receiver of the 30 meter radio telescope of the Institut de Radioastronomie Millimetrique (IRAM). Three such modules will be used in a 3 X 3 array operating near 230 GHz frequency. We discuss the requirements on the performance of the multibeam receiver module and compare it with a single beam receiver arrangement. After the presentation of a single mixer receiver operation the performance of the three mixer module is described. The basis for the integration of several SIS mixers with a common local oscillator source is given by the saturation of the SIS receiver noise dependence upon local oscillator power. The 1.3 mm SIS mixer block is built with a reduced height waveguide. The individual SIS junction area is 2.2 micrometer2 with a Josephson critical current density of about 3.6 KA/cm2. The minimum SSB receiver noise temperature at 230 GHz in a single beam receiver is as low as 50 K. In the module a common local oscillator power source is connected to the three mixers through a common three branch directional coupler. The performance of the three mixers is nearly identical across the 200 - 250 GHz band. The minimum DSB receiver noise temperature of 37 K is obtained simultaneously in all three channels around 230 GHz.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alexandre Karpov, Alexandre Karpov, J. Blondel, J. Blondel, Matthew Carter, Matthew Carter, Bernard Lazareff, Bernard Lazareff, D. Billon-Pierron, D. Billon-Pierron, K. H. Gundlach, K. H. Gundlach, } "Multibeam SIS mixer module for a focal plane array receiver", Proc. SPIE 3357, Advanced Technology MMW, Radio, and Terahertz Telescopes, (31 July 1998); doi: 10.1117/12.317413; https://doi.org/10.1117/12.317413
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