2-TERMINAL MILLIMETER-WAVE SOURCES

Basic principles of operation, fundamental power-generation capabiliti es, and fabrication technologies are reviewed for three groups of two- terminal devices, i.e., resonant-tunneling diodes (RTD's), transferred -electron devices (TED's), and transit-time diodes. The paper focuses on devices for frequencies above 30 GHz, and an overview of recent res earch in this area and of various state-of-the-art laboratory results is given. As an outlook, the potential of some new material systems fo r high-power devices is discussed.