Design and development of 3 kW pulsed solid-state RF power amplifier using two LDMOS in parallel configuration at 1 MHz

Abstract

A 3 kW and 1 MHz pulsed solid state RF amplifier has been designed and developed to drive TH581 tetrode tube based RF amplifier to realise 100 kW pulsed RF source. The driver amplifier is operated with 1 ms pulse width at 50 Hz repetition rate. The 3 kW RF power is obtained by operating two Gemini pair LDMOS transistors (VDD=50 V) in parallel configuration at device itself and having single ended topology with common lumped element based input and output matching network. The amplifier delivers 3 kW RF power when fed by 25 dBm RF input drive from the signal generator. This scheme eliminates the need of RF combiner and divider which results in low loss, high efficiency, lesser number of components, simple and compact design.