A 250 GHZ PLANAR LOW-NOISE SCHOTTKY RECEIVER

A planar quasi-optical Schottky receiver based on the quasi-integrated horn antenna has been developed and tested over the 230-280 GHz bandw idth. The receiver consists of a planar GaAs Schottky diode placed at the feed of a dipole-probe suspended on a thin dielectric membrane in an etched-pyramidal horn cavity. The diode has a 1.2 mum anode diamete r and a low parasitic capacitance due to the use of an etched surface channel. The antenna-mixer results in a measured DSB conversion loss a nd noise temperature at 258 GHz of 7.2dB +/- 0.5dB and 1310K +/- 70K, respectively, at room temperature. The design is compatible with SIS m ixers, and the low cost of fabrication and simplicity makes it ideal f or submillimeter-wave imaging arrays requiring a 10-20% bandwidth.