Integrated superconducting receivers

Abstract

The concept of a fully superconducting integrated receiver is developed and experimentally tested. This single-chip sub-mm wave receiver includes a planar antenna integrated with a SIS mixer and an internal superconducting Josephson-type local oscillator (flux-flow oscillator, FFO). The receiver is tested with a DSB noise temperature below 100 K around 500 GHz being pumped by its internal local oscillator (LO). The instantaneous bandwidth of 15-20% is estimated via FTS and heterodyne measurements that meet the requirements of most practical applications. The far field antenna beam is measured as ≈f/10 with sidelobes below -16 dB that is suitable for coupling to a real telescope antenna. A nine-pixel imaging array receiver with each pixel containing an internally pumped receiver chip is developed and tested. A linewidth of the phase locked FFO as low as 1 Hz is measured relative to a reference oscillator in the frequency range 270-440 GHz. An rf amplifier on the base of a dc SQUID is developed and tested showing a noise figure below 10 K at 4 GHz and a bandwidth of about 300 MHz. This amplifier can be included as a part of an integrated receiver that is valuable for array applications.