High-Efficiency D-Band Monolithically Integrated GaN SBD-Based Frequency Doubler With High Power Handling Capability

A high-efficiency ${D}$ -band monolithically integrated GaN frequency doubler based on a pair of antiseries four-anode planar GaN Schottky barrier diodes (SBDs) has been successfully fabricated. Unlike the traditional hybrid integrated circuit technology, the monolithic integrated circuit technology has been used in the design and fabrication of GaN SBD-based frequency doubler circuits to achieve good alignment and low conversion losses. At room temperature, the experiments show that the peak conversion efficiency reaches 17.0% at 115.6 GHz under a continuous wave (CW) driving which is a critical requirement for many practical applications. The efficiency of 17.0% is the highest efficiency of GaN SBD-based multipliers at present under CW driving mode. This monolithically integrated doubler also exhibits a broadband high efficiency characteristic of more than 4.7% (−5.58 dB from 17%) across a 10% band from 109 to 121 GHz. In addition, high CW power handling capability of the proposed frequency doubler is verified. The experiments show that the frequency doubler can endure a maximum CW input power of 0.5 W.