DEVELOPMENT OF HIGH POWER CW X-BAND TRANSFERRED ELECTRON OSCILLATORS.

A research and development program on high power cw transferred electron oscillators (TEOs) in X-band is described. The objectives of the program were: (a) to obtain a power output of 500 mW, (b) a minimum operating life of 1500 hours, and (c) to design and fabricate a metal-ceramic microstrip circuit for TEOs. All these objectives were successfully met. The highest power output obtained from a single device was 700 mW at 8.75 GHz with an efficiency of 2.7%. Twenty-five devices with power outputs ranging from 50 mW to 670 mW were delivered to the contracting agency. This report describes the efforts on GaAs materials technology, device fabrication technology, and the device-circuit study. A preliminary study of the effect of second harmonic tuning on the dc/rf conversion efficiency is also described. The design criteria for a metal-ceramic microstrip circuit are discussed along with the details of fabrication of such circuits. A device on life test has logged over 16,000 hours with stable power output. (Author)