多载波航天测控雷达发射机功放的线性化

某航天测控雷达发射机采用速调管进行主功率放大，而速调管线性差，三阶交调指标不满足要求，影响雷达性能。该文利用三阶多项式来表征速调管的非线性特性，并根据测试数据确定多项式系数，计算出速调管增益压缩特性；然后提出一种顸失真方法，利用两路载波信号频率合成得到预失真三阶信号，将此信号与载波信号合成后送入速调管共同放大，通过调整预失真三阶信号的幅度和相位来抵消载波信号放大后产生的三阶交调信号而达到线性化。最后根据算出的速调管特性设置仿真条件进行了仿真。结果表明，此方法可使三阶交调指标改善10．5dB左右，从而使指标符合要求。该方法原理清晰，电路简单，效果明显，可以显著改善三阶交调，从而提高雷达性能。

Linearization of Power Amplifier in Multi-Carrier Radar Transmitter for Space Instrumentation and Command Network

The transmitter of a kind of space instrumentation and command radar uses the klystron to enlarge the main power,but the klystron linearity is bad,and the index of IMD3 don't satisfy the requirement,which affects the radar performance.This article uses third order multinomial to describe the klystron nonlinear response,and determine the multinomial coefficient and calculate the gain compress characteristic by test data.A predistortion method is proposed,first obtaining the third order signals of predistortion by synthesizing the two carrieres,and then sending this signal with the carrier to klystron,at last reaching the linearization by adjusting magnitude and phase of the three order signals to counteract IM3.According to the gain compress characteristic simulation conditions are set.The result of simulation shows that IMD3 can be improved about 10.5dB.This method has clear principle,simple electric circuit and obvious effectiveness,and IMD3 is obviously improved,thus improving the performance of the radar.