Abstract: A GaAs monolithic waveguide switch and system for low power consumption and high frequency switching wherein a single GaAs chip is flip-chip mounted onto a waveguide slot and inserted between interconnecting waveguides to provide single pole single throw switching. The GaAs chip includes an array of MESFETs along with connecting electrodes configured to provide low loss in the biased state and high loss in the unbiased state. The use of a single GaAs monolithic chip provides improved RF performance and manufacturability over discrete devices and provides lower power consumption as compared with silicon PIN diode waveguide switches.