Wide-Band Quasi-Optical SIS Mixers for Integrated Receivers up to 1200 GHz
S. V. Shitov, A. M. Baryshev, V. P. Koshelets +5 more
Introduction Recently demonstrated integrated receiver [1] comprising a planar-antenna SIS mixer and a superconducting local oscillator based on FFO (Flux-Flow Oscillator), is limited in its frequency range by the SIS mixer as well as by the FFO. The coupling between FFO and mixer determines the effective bandwidth and could potentially be several hundreds of GHz. Recent development of all-Nb superconducting integrated receivers has demonstrated that the frequency of a single FFO can be tuned from 200 to 700 GHz [1],[2], i.e. up to the gap frequency of Nb. If the material with higher gap frequency (NbN for example) is used, the FFO can be running up to nearly two times this frequency, so up to 1200 GHz. However, the coupling of signal into SIS mixers with Nb tuning structures is found to be decreased rapidly above the gap frequency (about 700 GHz for Nb). This problem can be solved by using a normal metal such as aluminium for the coupling structures [3], [4]. In this contribution we present both calculated and experimental results of Nb-based SIS mixers in combination with a double dipole planar antenna for the highest possible frequencies. Special attention is paid
•Mar 1, 1996•1 citation