Planar Quasiparticle Mixer Structures for Millimeter and Sub-Millimeter Wave Receivers

The paper covers various aspects of integrating planar antennas with superconducting mixers in the millimeter and sub-millimeter wave regime. The construction of an 80-100 GHz tapered slot antenna and SIS mixer chip with a minimum double side band noise temperature of 240 K is described. An experimental study has been made of the properties of slot lines and of some slot line components on substrates with dielectric constants similar to that of silicon. The slot wavelengths, radiation and substrate mode losses have been measured. A way of determining the embedding admittance of SIS mixers, the "Voltage Matching Method", is presented. It is similar to some older techniques, but is more efficient and excutes more than 2000 times faster on a computer. An antenna configuration with a broadside dipole array antenna mounted to a dielectric lens has been studied in a scale model. The antenna is well suited for integration with planar mixers, and has a linearly polarized beam of approximately equal width all planes. The measured bandwidth is one octave. Antenna diagrams are also presented at frequencies around 100 GHz. Three SIS receivers operating at respectively 100, 400 and 480 GHz are reported. The 480 GHz receiver gave a best noise temperature of 200 K DSB, which is better than any other open structure SIS receiver in this frequency range that has been reported in the literature. An SIS receiver that uses a dipole array antenna in an endfire configuration is also described