Development of a Compact 340 GHz Receiver Front-End

Paper in proceeding, 2009

A compact 340 GHz roomtemperature receiver front-end module has been developed consisting of a subharmonic Schottky diode mixer module with an integrated LNA. A novel sideband separation topology has been evaluated by using a pair of the developed mixers interconnected by external waveguide branch guide coupler hybrids for the LO and RF feedings and coaxial IF hybrids, measuring sideband suppression levels of 5dB to 15dB over the 315-365 GHz band. For efficient LO pumping of the image rejection mixer, a novel high power LO chain based on a 5 x 34 GHz HBV quintupler (170 GHz LO source) has been developed with an ultra compact mechanical block housing, not much larger then a waveguide flange. The HBV LO source has been compared to a broadband medium power source consisting of a W-band active multiplier module, based on commercial MMIC chips from Hittite, followed by a medium power Schottky doubler from VDI. The demonstrated compact receiver front-end has considerably reduced size and weight owing to the high multiplication factor of the compact LO chain and mixer integrated LNA. The novel image rejection topology resolves the standing wave issue of a previously proposed topology, improving both the image rejection response and reducing the standing waves at the LO and RF ports.