S-BAND HIGH POWER SOLID-STATE AMPLIFIER DESIGN AND DEVELOPMENT

摘要

The design and development of a 230 W power amplifier operating at S-band (2.35 to 2.45 GHz) is described. The motivation behind this development is the need for a microwave driver amplifier to be used in the linear accelerator facility at the Institute of Accelerating Systems and Applications at the University of Athens. It will replace the magnetron currently being used at low microwave power. The need for extremely stable microwave power for the electron beam pre-acceleration and chopping cavities makes it imperative to use a solid-state high power GaAs amplifier. The design technology uses microstrips, fabricated on RO4003 substrates, and special care has been taken to protect the amplifier from over temperature and overload. The amplifier is composed of three stages. The first is a MMIC and the other two use GaAs MESFETs. The amplifier also has forward and reflected signal indicators that can be used for remote amplifier control to shut it down if the VSWR is too high, for example, or to check the RF output level and provide automatic gain control. The amplifier was designed using a CAD program, which gave the flexibility to use robust optimizer tools for the complete design of the RF chain. Finally, test results are presented that show excellent agreement with the theoretical predictions.