Millimeter-wave gyro-amplifiers: principles and state-of-the-art

The continuing need for high-power, broadband sources of millimeter-wave radiation has led to extensive research in the area of gyrotron amplifiers. Several key issues in the design and development of gyro-amplifiers, including stability, bandwidth, high-average power capability, operation in high-order modes, and driver availability, are discussed. State-of-the-art Ka- and W-band gyro-amplifiers, each of which has addressed one or more of these key issues, are described.