散射矩阵同时测量的一种新方法

A NEW METHOD OF THE SIMULATANEOUS SCATTERING MATRIX MEASUERMENT

该文提出了散射矩阵同时测量的一种新方法—频域分割法。这种方法的基本原理是:发射时水平极化天线和垂直极化天线同时发射两个中心频率不同、调频斜率相同的线性调频信号,中心频率的差值等于或略大于信号带宽,接收时上述的两个天线同时接收,那么每个天线接收的回波是两个不同极化组合回波的叠加,我们利用两个回波信号频谱的差异,将之分离,从而实现散射矩阵的同时测量。这种方法避免了测量不同时以及极化开关造成的极化耦合而引起的测量误差,与散射矩阵同时测量的信号编码法相比,更容易实现高极化隔离度。

This paper explores a new method of the simultaneous scattering matrix measurement-dividing in frequency domain. In this method, two chirp signals with same slope but different central frequency are transmitted simultaneously through two antennas. One is a horizontal polarization antenna and another is a vertical polarization antenna. The dispersion of the two central frequencies is not smaller than the bandwidth of the chirp signals. The return signals are received through two antennas simultaneously. Each antenna receives a signal that is the superposition of two return signals with different transmitting-receiving polarization. These signals are divided in frequency domain making use of the difference of their spectra. By this way, all the four elements of the scattering matrix can be measured at the same time. By this method, the measurement errors caused by polarization switch or asynchronous measurement are avoided. Compared with the method of simultaneous scattering matrix measurement through signal coding, this method is easy to get much higher polarization isolation.