200 GHz WAVEGUIDE BASED SITBHARMONICALLY PUMPED MIXERS WITH PLANAR SCHOTTKY DIODES

Extremely sensitive subharmonically pumped mixers (SHPMs) have been developed that utilize planar Schottky diodes fully integrated with the appropriate circuitry on a quartz substrate. The successful demonstration of these low noise mixers relied on several new technologies such as the development of the QUID (Quartz substrate Up-side-down Integrated Device) process and the successful use of T-gate like structures for low parasitic Schottky contacts. Based on these technologies, 200 GHz SHPMs measured in our lab have achieved better performance than any previously reported whisker contacted or planar Schottky diode SHPM at comparable frequency. In fact, the achieved noise sensitivity is only about 1.5 times worse than the best ever whisker contacted fundamental mixers at this frequency.