Design of GaN-based components and application to high-power antenna

This work demonstrates the feasibility of using gallium nitride (GaN) technology in reconfigurable RF systems. GaN-based varactor diodes and switch circuits are pursued as promising candidates for high-power/high-frequency applications. The first part is devoted to active GaN device development. Active components were realized using the Canadian National Research Council (NRC) GaN HEMTs process. Based on three process, such as, GaN150v0 (gate length of 0.15um), GaN500v1 and GaN500v2 (both with gate length of 0.5um), many varactor diodes with size different have been manufactured and characterized via DC and RF smallsignal and large-signal measurements. Then, the varactor diodes were modeled by analytic equations containing empirical coefficients. These expressions have been introduced for the first time for the voltage dependency of equivalent capacitance (CEq) and series resistance (REq) and can be used as a general model to represent the nonlinear behavior of GaN based varactors. For small-signal operation, all of the developed equations describing REq and CEq are only bias voltage and device geometry dependent.