Abstract: Flip chip monolithic microwave integrated circuits (MMIC) devices formed on gallium arsenide substrates and use thermally bumped diodes and field effect transistor devices to achieve improved heat dissipation and power protection. Flip chip limiter MMIC devices and transmit/receive switch MMIC devices are specifically provided by the present invention. The flip chip gallium arsenide limiter and transmit/receive switch MMIC devices use plated metallized bumps for both I/O connections and for thermal connections to a host substrate (aluminum nitride). The present invention also incorporates coplanar waveguide transmission line, thereby eliminating backside processing of the gallium arsenide substrates. The transmit/receive switch device provides power protection in both transmit and receive modes.