时间调制阵列天线的非理想波形调制研究

针对时间调制阵列天线中射频开关的非理想特性，开展了多种波形调制下的谐波特性研究.首先，推导了非对称梯形波/升余弦波周期调制的傅里叶系数，分析两种调制波的非对称性对各次谐波的幅度、相位和能量占比的影响；在此基础上，通过实验获得了一组实验调制波，并运用三角函数多项式拟合真实调制波形的上升沿与下降沿；最后，讨论了各种波调制与实测谐波分量的差异性.结果表明，与已有调制波相比，本文所提出的非对称梯形波、非对称升余弦波和拟合波的调制更接近真实波调制.

Research on non-ideal waveform modulation of time modulation array antenna

In this paper, aiming at the non-ideal characteristics of the radio frequency switch in the time-modulated array antenna, the harmonic characteristics of various modulation waveforms are studied. First, the Fourier coefficients of the asymmetric trapezoidal/raised cosine waveforms are deduced, and the influence on amplitude, phase and energy proportion of two waveforms are analyzed. On this basis, an experimental modulation waveform are obtained through experiments, and trigonometric polynomials are used to fit the rising and falling edges of the real modulation waveform. Finally, the difference between various waveforms and harmonics is discussed. The results show that compared with existing modulation waveforms, the modulations of the asymmetric trapezoidal waveform, asymmetric raised cosine waveform and the fitted waveform proposed in this paper are closer to real waveform.