A 94 GHz monolithic switch with a vertical PIN diode structure

This paper presents the design, fabrication, and performance of a 94 GHz monolithic PIN diode SPDT switch. The switch uses a vertical PIN diode structure to achieve insertion loss of 1.0 dB and isolation greater than 30 dB at 94 GHz, The circuits were fabricated on semi-insulating GaAs wafers with MOCVD grown p+, i, and n+ layers. An AlGaAs layer was used as an etch stop in the fabrication of the backside via hole. Measurements were made in a fixture containing transitions from WR-10 waveguide to quartz microstrip and from the quartz microstrip to the MMIC chip.