Method to reduce control voltage for high power GaN RF switches

A gate bias circuit is presented that allows high power RF switches to operate at rated power with a reduced control voltage. The approach utilizes resident circuit elements such that it can be monolithically implemented with existing designs. To demonstrate the technique a 40W SPDT GaN switch MMIC designed for -40V control was retrofitted with the proposed gate circuit and fabricated adjacent to the original version to facilitate a meaningful comparison. Measured results demonstrate up to an order of magnitude increase in power handling for the modified design when operated at a -10V control over that of the original circuit. No discernible DC power draw from the control voltage source and little or no degradation in insertion loss was observed for the switch with the proposed gate bias circuit.