Design of a Subharmonic 340 GHz GaAs Schottky Diode Mixer on Qaurtz with Integrated Planar LO-IF Duplexer

Paper in proceeding, 2006

A fixed tuned 340 GHz sub-harmonically pumped GaAs schottky diode mixer design is presented. The design consists of a 50 µm thick quartz microstrip circuit mounted in a full height waveguide splitblock and uses a flip-chip mounted VDI SC1T2-D20 anti-parallel diode pair. The RF and LO waveguide to microstrip transitions are located at each end of the substrate and a planar LO-IF duplex filter has been integrated with the mixer circuitry, providing for the possibility of planar LO feeding in the future. A comparison of the coaxial with the lumped port method for EM modeling of the diode is presented, showing good agreement between the two methods. The diode parameters and IV characteristics have been matched with a standard diode model used in the harmonic balance analysis of the complete mixer circuit. Preliminary test results from a conceptually scaled 110 GHz mixer design using the UMS DBES105a schottky diode chip are presented showing a conversion loss of 10.8 dB with 3 dBm of LO power.