High Power L-Band T/R Module Utilizing GaN HPA for Satellite Use

Abstract

High power L-band T/R (Transmit and Receive) module has been developed by applying GaN HEMT to the HPA (High Power Amplifier) in transmitter. 34W of output has been achieved with 41% power efficiency and small component size, realized by GaN HPA superior performances compared to the conventional device such as GaAs. The most challenging technical aspect in adapting GaN technology in space environment was to maintain both Multipactor avoidance and RF performance, which was solved by electromagnetic simulated design and verified through environment tests. SQT on GaN HPA and T/R module was also completed to assure their enough reliability for satellite use. I. Introduction /R (Transmit and Receive) module is a key component for radar array systems, as a large number of units are mounted on their antenna panels which can form RF signal beams. To improve the radar system performance, T/R module is required to increase TX (Transmitter) power and to improve RX (Receiver) noise figure. As one solution to increase TX power, one of the wide-band-gap devices ‘GaN (Gallium Nitride) HEMT (High Electron Mobility Transistor)’ has been recently applied to HPA (High Power Amplifier), but only for ground system applications yet. The advantage of GaN HPA is achieving higher TX power with smaller size by virtue of its higher power density and better efficiency compared to the conventional device such as GaAs (Gallium Arsenide). However, the component design engineers have not been encouraged to use GaN HPA for space application due to its disadvantages of higher DC bias voltage operation and lack of reliability test data. This paper describes the development of L-band high power T/R module for actual satellite program utilizing GaN HPA, by solving technical difficulties.