Superconducting chip receivers for imaging application

Experimental details of a unique superconducting imaging array receiver are discussed. Each pixel contains an internally pumped receiver chip mounted on the back of the elliptical microwave lens. Each chip comprises a quasi-o ptical SIS mixer integrated with a superconducting flux-flow oscillator (FF O) both fabricated from the same Nb/AlOx/Nb trilayer on a silicon substrate . Properties of the integrated lens antenna were studied using an externall y pumped reference SIS mixer which showed antenna sidelobes below -17 dB an d a receiver double side band noise temperature, T-RX(DSB), below 100 K wit hin the frequency range 460 - 500 GHz that is close to the quantum noise. F or the imaging array T-RX(DSB) = 150 K has been measured at 500 GHz using t he internal flux-flow oscillator as a local oscillator (LO). A balanced SIS mixer was tested showing T-RX(DSB) < 100 K within the range of 480 - 510 G Hz using the internal LO. A computer system was developed to control simult aneously the de bias of the SIS mixer and the frequency and power provided by FFO. The system also performs automatic optimization of the receiver noi se temperature.