Ka频段GaN功放的预失真线性化器设计

Design of Pre-distortion Linearizer for GaN Power Amplifier at Ka-band

摘要:

基于满足目前高效复杂的调制技术对功率放大器线性化度越来越高的需求的目的,采用模拟预失真技术设计了一种线性化器,用来改善Ka频段氮化镓(GaN)固态功放的非线性化失真。通过改进传统的并联式二极管预失真电路,采用开环技术,将两个肖特基二极管并联。改变二极管的偏置状态,得到不同的改善程度的预失真信号。结合使用专用电磁仿真软件ADS2013做电路仿真,通过参数扫描得到二极管偏置状态的初始值,为实物调试提供理论基础。通过对已加工的实物测试,结果表明：增益幅度补偿达到6.4dB,相位补偿达到28°。

Abstract:

Based on the current high efficiency and complex modulation technology, the demand for the linearization of power amplifier is higher and higher, a linearizer using analog pre-distortion is proposed in this paper to improve the non-linear distortion of GaN power amplifier at Ka-band. It is improved on the basis of traditional pre-distorter and composed of two parallel Schottky diodes using open loop method. It can generate the distorted signals which are on different degree of improvement through changing the offset state of the diode. The initial value can be gained by using the ADS2013 which is specialized electromagnetic simulation software. Then the value gained provides the theoretical basis for physical object debug. The physical object tests show that the linearizer can provide 6.4dB gain expansion and 28° phase expansion.