Progress in the development of SIS quasiparticle mixers

A summary is presented of recent SIS quasiparticle heterodyne mixer work done at Berkeley. Developments related to millimeter wavelength waveguide mixers include techniques for accurate measurements of noise and gain, integrated RF matching elements for large instantaneous bandwidths, large scaled modeling experiments, new W-band mixers with wide tuning bandwidth and only one mechanical adjustment, observation of very large coupled gain, systematic studies of the properties of array mixers, analysis of the effect of saturation on mixer measurements, very low noise in mixers with high quality junctions, and computer modeling to test the quantum theory of mixing. Developments related to planar lithographed mixers with quasi-optical antennas include construction of test apparatus, large scale modeling, and the design and evaluation of mixers which use RF matching structures integrated with bow tie antennas.