A full-band waveguide SIS receiver with integrated tuning for 75-110 GHz
Abstract
The performance of a broadband SIS (supercondcutor-insulator-superconductor) receiver with no mechanical tuning elements was modeled and tested. The mixer mount had a broadband-waveguide-to-microstripline transition consisting of a four-step Chebyshev single-ridge transformer. The last step of the ridge connected the waveguide to a microstripline circuit. The on-chip circuit consisted of a microstripline that transmitted the RF and the local oscillator signals to the SIS mixer. Both the SIS element and the inductor had RF grounds provided by 90-deg radial stubs. The inductor tuned out the junction capacitance to allow operation over the full frequency band. The SIS element can be a single junction or series array using Nb/AlO(x)/Nb trilayer tunnel junctions with areas as small as 0.5 sq microns and Vm(2 mV) = 39 mV. Preliminary results indicated a DSB receiver noise temperature of 65-80 K across the band measured at 4.4 K with an internal cryogenic RF hot/cold source and with T(if) = 21 K. With another device, a mixer noise temperature of 35 K at 100 GHz was acheived, increasing to 45 K at 79.5 and 110 GHz. Coupled mixer gain of up to +3 dB and negative dynamic resistance on the first photon step were observed.
- Publication:
-
IEEE Transactions on Magnetics
- Pub Date:
- March 1991
- DOI:
- 10.1109/20.133752
- Bibcode:
- 1991ITM....27.2634W
- Keywords:
-
- Mixing Circuits;
- Radio Receivers;
- Sis (Superconductors);
- Volt-Ampere Characteristics;
- Waveguide Tuners;
- Aluminum Oxides;
- Cryogenic Equipment;
- Double Sideband Transmission;
- Electron Tunneling;
- Niobium;
- Electronics and Electrical Engineering