High-Performance RF Balanced Microstrip Mixer Configuration for Cryogenic and Room Temperatures

Abstract

A high-performance S-band down-conversion microstrip mixer, for operation from 77 K to 300 K, is described. The balanced mixer combines a 90 degree hybrid coupler, two Schottky diodes, a band pass filter, and a low pass filter. The coupler phase shift drastically improves noise rejection. The circuit was implemented according to the configuration obtained from extensive simulation results based on electromagnetic analysis. The experimental results agreed well with the simulation results, showing a maximum measured insertion loss of 0.4 dB at 2 GHz. The microstrip mixer can be easily adjusted to different frequency ranges, up to about 50 GHz, through the proper choice of microstrip configuration. This novel S-band cryogenic mixer, implemented without resorting to special components, shows a very high performance at liquid nitrogen temperatures, making this mixer very suitable for high-temperature superconductive applications, such as front-ends.

Efficiency Improvement of an Electric-Grid Transformer Using the Diamagnetism Characteristics of a Bulk Superconductor

“…The table refers to the different transformer's configuration characteristics, such as: dimensions, operating frequency, Environmental temperature and the iron losses with no load. The data in the table indicate that the dimensions of the BSST model are relatively smaller than those of the commercial transformers, in addition, this type of transformer will have to work under cryogenic cooling conditions [31]. Another notable issue is that the change in the iron losses between the conventional and the BSST is negligible compared to the improvement in the output power.…”

Very Low-Noise Figure HTSC RF Front-End

“…The cryogenic measurement system is illustrated in Figure A1. The system is composed of three main elements: a Vector Network Analyzer (VNA), a computing system, and a polystyrene liquid-nitrogen container [30,31]. The S-Parameters were measured using the VNA, and the Device Under Test (DUT) was immersed in liquid nitrogen.…”