Tunable Matching Circuit for Millimeter Wave Superconductor-Insulator-Superconductor Mixers
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
The use of the kinetic inductance of an array of superconductor-type Josephson junctions to adjust the operating frequency will allow precise in situ tuning of a resistance, inductance, capacitance (RLC)-type circuit, which is important for mixer applications. In the RLC circuit, the inductance is varied by adjusting the direct current (DC) through a single Josephson junction or an array of Josephson junctions. This allows control over the frequency at which the attached superconductor-insulator-superconductor (SIS) mixer circuit can operate. (Image Omitted) SIS tunnel junctions have found significant applications as quantum-limited mixers in the millimeter (mm) wave region. The junctions are biased near the energy gap on the quasiparticle characteristic, and mixing occurs due to its highly nonlinear nature.