Planar varactor diodes for millimeter and submillimeter wavelengths

Schottky barrier varactor diodes are used as frequency multipliers to supply local oscillator power for heterodyne receivers at millimeter and submillimeter wavelengths. Whisker contacted GaAs Schottky varactor diodes are the most common high-frequency multiplier element in use today. They have been used in heterodyne receivers for ground based, airborne and space applications. Although the whisker contacted Schottky varactor diodes have proven very effective, there remains great interest in developing technologies which are more mechanically robust, have the potential to deliver larger amounts of power and are capable of operating at higher frequencies.;The doubler chips for the 1 THz multiplier chain incorporate multiple diodes for increased power handling ability, and are designed to be used in a balanced doubler circuit. Each device consists of four varactor diodes integrated on a single chip.;Developing a tripler to 1 THz is the most challenging part of the project. The best devices today for this application are whiskered contacted Schottky diodes. To develop a planar tripler chip, we need to investigate novel varactor structures. A number of devices are being investigated as potential frequency doublers and triplers. An anti-series ;This research represents the first steps toward achieving the goal of developing an all-solid-state source for 1 THz. The system consists of two doublers (nominally 80 to 160 GHz and 160 to 320 GHz) and a tripler (320 to 960 GHz). An initial step in our development of planar Schottky barrier varactor diodes was to fabricate a planar device to replace the 6P4 diode, a very successful whiskered varactor diode used for doubling in the millimeter wavelength range.