AN X-BAND 100 W GAN HEMT POWER AMPLIFIER USING A HYBRID SWITCHING METHOD FOR FAST PULSE SWITCHING

This paper presents a new hybrid switching technique for enhanced pulsemode solid-state power amplifiers (SSPAs). In the proposed technique, pulse timing for bias stabilization is effectively decoupled from pulse amplification. The decoupling allows fast pulse switching by reducing the pulse width and increasing the pulse repetition frequency (PRF). The new switching method is applied to an X-band SSPA using GaN HEMT. The advantage of the proposed method is demonstrated by its excellent pulse characteristic. The proposed technique achieves a fast PRF of 100 kHz and a narrow pulse width of 1μsec. The measured rise/fall time(RFT) is 12.5/11.1 nsec, which is more than four times less than that of previous works. In addition, an excellent pulse droop of 0.43 dB is achieved with an output power of 51.3 dBm at 9.9 GHz. The fabricated SSPA shows a maximum output power of 135 W, a small signal gain of 47 dB, and power added efficiency (PAE) of 28.2% at 9.9 GHz. These results show that the proposed pulse switching technique provides a promising solution for SSPAs using a high-power GaN HEMT.