4-W IMPATT AMPLIFIERS FOR 6-8 GHz 1800CH FM RADIO SYSTEMS.

The development of an all solid-state microwave multiplex communication equipment depends on the realization of an all solid-state transmitter power amplifier. At present, Si IMPATT is considered the most promising solid-state device for obtaining both high output power and high reliability. A 4-W IMPATT amplifier with 10 dB gain has been developed by utilizing two Si DDR IMPATT diodes, with a 2. 5-W oscillation output power, in two cascaded stages for use as an all solid-state power amplifier of the 1800 channel radio transmission equipment in the 6 to 8 GHz frequency range. This paper describes the construction, the measured input vs. output power characteristics, the thermal noise characteristics, and the AM-PM conversion coefficient of the amplifier. The paper also describes the theoretical analysis of power combining obtained by cascade connection of the amplifier and the evaluation method of thermal noise caused when an IMPATT amplifier is used as the transmitter power amplifier of an FM transmitter-receiver. The text of this paper is in digest form.