A resonant cavity combined solid-state amplifier system including a resonant cavity having at least one output port coupled to a high-power transmission line. A plurality of high-power transistors are each configured to generate a variable amount of power input directly into the resonant cavity. The plurality of high-power transistors may be configured such that a failure of one or more of the plurality of high-power transistors does not substantially impede operation of the resonant cavity. A plurality of output impedance matching networks each coupled to one of the plurality of high-power transistors and extending into the resonant cavity are configured to match an impedance of each transistor to an impedance of the resonant cavity and configured to electromagnetically couple power from each of the plurality of high-power transistors into the resonant cavity to provide a combined high-power output to the high-power transmission line.