More Than 4 Percent Efficiency Solid-State Transmitter for 4 GHz Radio Relay

This paper describes a 4 GHz transmitter developed by using a low-level varactor up converter and a high-gain transistor injection locked amplifier. This transmitter, permitting obtain an RF output of 220 mW at an efficiency of more than 4% for a DC input of 5 W, is usable as a transmitter or exciter for radio relay of a maximum of 1380 channels.