Analysis and design of wide-band power amplifier using GaN

This paper presents analysis and design of wide band power amplifiers. Two types of 20Watt broadband power amplifier-I and amplifier- II using GaN have been designed. The RF performance of the broadband amplifier-I (Non Feedback matching networks) has been compared with the broadband amplifier-II (Conventional Feedback matching networks). It achieves 20 Watts output power with 12dB ± 1.0dB gain from 500 MHz to 2500 MHz at V_DS=28V. The broadband amplifier-I shows a significantly improved return loss and size. The broadband amplifier-I also has an efficiency improved by 6 percent with gain increased by 2.3dB from 500MHz to 2.5GHz. At lower frequencies from 500 MHz to 1000 MHz, the output power is 20 Watts with 40% efficiency. In addition, a broadband choke structure with a new technique was developed to obtain good isolation and low loss over the desired bandwidth.