Design and Realization of a 434 MHz, 200 Watts Solid-State Power Amplifier for a Microwave Hyperthermia System

This paper presents a class-B power amplifier (PA) for a microwave hyperthermia system. The power amplifier has been designed and fabricated for the operating frequency of 434 MHz with a Silicon based LDMOS field effect transistor as the main power device. During the design process, source-pull and load-pull techniques were used for determining the optimal impedance in order to obtain maximum Power Added Efficiency (PAE) whereas the output power should be maintained higher than 53 dBm. The average power-handling capability (APHC) of the microstrip lines in the PA circuit and proper heat sink for the proposed power amplifier are taken into account and presented. As a result, our power amplifier achieves a peak PAE of 45.8% with a gain of 18.9 dB and typical output power of 53 dBm (with 34 dBm input power).