A 250 GHz monolithic Schottky-diode receiver based on a double-slot antenna is presented. The double-slot antenna is placed on an extended hemispherical high-resistivity silicon substrate lens. The measured DSB conversion loss and noise temperature at 258 GHz are 7.8 & 0.3 dB and 1600 f l00K for the antenna-mixer, respectively. A nonoptimal polyethylene Xd/4 matching-cap layer for the silicon lens improves the conversion loss and noise temperature by 1 dB, and another 0.7 dB improvement could be obtained with the use of a more optimal matching cap layer. The uniplanar double-slot antenna receiver is less than 0.3 x 1 mm in size including the IF filter and represents the first fully monolithic 250 GHz receiver to date. The measured performance is within 2-3 dB of the best 200' GHz waveguide receivers using planar Schottky diodes.'
I. INTRODUCTLON"GRATED-CIRCUIT receivers consisting of a planar
I antenna integrated with a matching network and a planarSchottky-diode or a three-terminal device offer many advantages over waveguide-based receivers at millimeter-wave frequencies. They are smaller, lighter, and less expensive to build than waveguide systems and can be easily produced in. large numbers for millimeter-wave applications. A potential candidate for excellent millimeter-wave performance is the double-slot antenna [2]- [4]. In this work, a planar Schottky diode and a CPW-line matching network are integrated with a double-slot antenna on GaAs to form a fully monolithic Schottky-diode receiver. The monolithic integration should result in minimum parasitic capacitance and series resistance. After fabrication, the double-slot receiver is placed on an extended hemispherical high-resistivity silicon substrate lens to result in high-gain patterns with high Gaussian coupling efficiency [5]. This design requires no via holes or a backing ground-plane. The GaAs substrate is therefore not thinned down to 100 pm (or less) thereby increasing the yield of the fabrication process. The application areas for this receiver are in millimeter-wave imaging arrays for remote-sensing and radio-astronomical systems. I 190 p Polveth Monolithic Double-slot Receiver 630 CaAs pm-thick wafer 570p"hick high-p Si wafer Ma