基于步进频连续波雷达的射频对消∗

摘要

连续波雷达相比于脉冲雷达具有小型化、低工作电压、高可靠性、高距离分辨率，以及不存在距离盲区等一系列优点。但是连续波雷达具有一个最大的问题就是信号泄漏问题，从发射机直接耦合到接收机的信号相较于远处的有用信号来说要大很多，当探测距离较远时就需要增大发射功率，这样直接耦合到接收机的信号就有可能淹没有用信号甚至烧毁接收机，这是连续波雷达不可避免的问题。在分析直接耦合信号的特性之后，运用射频对消技术构建一个与直接耦合的信号幅度相同，相位相差180°的信号在接收机前进行对消。整个射频对消系统经过测试得出在500 MHz的带宽内，对消比达到了30 dB以上。%Compared with the pulse radar,the continuous radar(CW)has the advantages of smaller size,lower operating voltage,higher reliability,higher range resolution and so on.But the biggest shortcom-ing of the CW radar is the large leakage.The signal which is directly coupled from the transmitter to the re-ceiver is much bigger than the useful reflection signals.For larger detection range,the power of the transmit signal must be increased.So the useful refection signal may be covered by the direct coupling and the receiver may be damaged.After analyzing the feature of the direct coupling signal,a signal which has the same ampli-tude as the direct coupling signal and the phase difference of 180°will be got through the RF cancellation sys-tem.From the measured result,the RF cancellation works well in a SFCW radar system and the cancellation ratio(CR)can get 30 dB in 500 MHz bandwidth.