一种消除功率放大器低频振荡的方法

A Method for Eliminating Low-frequency Oscillaton in Power Amplfiers

功率放大器是发射机的重要部件之一,在S波段GaN HEMT平衡功率放大器设计中常出现低频段振荡,为了消除这种类型的振荡,文中提出了在合成管GaN HEMT的栅极和地之间放置改进型的LCR复合有耗吸收网络的方法。由于吸收网络的电阻在低频段有效并入电路,在工作频段内被短路,因此,降低了带外低频端的高增益,从而消除了功率放大器电路中由于低频端增益过高产生的振荡,而对工作频带内的增益和驻波性能没有明显影响。

Power amplifier is one of the most important components of the transmitters.Low-frequency oscillation usually appears in S-band Balanced power amplifier（BPA） of GaN HEMT.An effective method for eliminating low-frequency oscillation is proposed,that is,a complex lossy LCR absorbing network is placed between gate electrode of GaN HEMT and ground.Since the resistance of the absorbing network is effectively paralleled into the circuit in low frequencies,while shorted in the work frequencies,the high gain of lower frequencies is reduced outside of working band and low-frequency oscillation is eliminated.Besides,the gain and VSWR performance change unobviously in working frequency band.