一种新型FMCW雷达射频对消方法

随着平台一体化及雷达系统微型化的发展,调频连续波(FMCW)雷达发射至接收的信号泄漏更为严重,信号泄漏已成为制约FMCW雷达系统性能的关键因素。为解决这一问题,提出了一种新型的射频对消方法以提高FMCW雷达的收发隔离度,利用FMCW雷达泄漏信号与回波信号在频域可分离特点,采用数字锁相环技术产生主动对消矢量信号,在给定FMCW雷达泄漏信号初值的条件下仿真分析对消比与相位误差、幅度误差的关系,建立了特定条件下的具有自适应功能的射频对消方案,并设计了验证电路以验证方案的可行性。验证结果表明该方法在1 GHz带宽内实现了优于25 dB 的对消比,且该对消电路具有低功耗、结构简单等优势。

Research on a Novel RF Cancellation Method for FMCW Radar

With the development of miniaturization and integration of radar system, the signal leakage from the transmitter to the receiver is more serious in FMCW radar. Signal leakage has become the key factor restricting the performance of FMCW radar system. The serious signal leakage will restrict the performance of FMCW radar system, and improving the isolation between transmitter and receiver has become an important part of system research. To solve this problem, a novel RF cancellation method to improve system isolation is proposed and experimentally demonstrated basing on the separable feature of FMCW radar in frequency domain between the leakage signal and the echo signal. The digital phase locking loop (PLL) is used in this method to produce the cancellation vector signal. By studying the relationship between the cancellation ratio and the phase error, amplitude error, a radio frequency cancellation scheme with adaptive function under the given initial value of the leakage signal is established. The proposed RF cancellation method achieves cancellation ratio better than 25 dB in the bandwidth of 1 GHz, and the RF cancellation circuit has the advantages of low power consumption and simple structure.