X-band predistortion linearized GaN HPA for broadband satellite communications

This paper presents a novel method of predistortion linearization for an X-band GaN High Power amplifier (HPA) in a broadband satellite communication transmitter. With parallel Schottky diodes integrated with a CPW line, predistortion transmission characteristics (AM-AM and PM-AM) are obtained as the reverse of the GaN HPA nonlinear-transmission characteristics in both magnitude and phase. Then an X-band linearized GaN HPA is developed and measured; the corresponding measurement shows that an IM3 improvement more than 10.7dB can be achieved within 7.9 to 8.4GHz at output power of 40dBm.