Ka频段射频对消连续波雷达前端研制

介绍了一种全模拟Ka频段自适应射频对消技术，用于解决连续波雷达收发隔离不足的问题。该技术利用了幅度相等、相位相反矢量叠加后相互抵消的基本原理，采用毫米波解调器把泄露信号分解为I、Q信号，经有源滤波放大网络后再通过毫米波矢量调制器构造出与泄露信号等幅反相的矢量，并通过波导耦合器馈入接收通道与泄露信号叠加达到对消效果。采用此技术，研制出了一台带对消器的Ka频段单天线连续波雷达原理样机，在600 MHz对消带宽内，对消度达到25 dB以上，最大对消度35 dB。

Design of Ka-band front-end with RF cancellation in continuous wave radar system

An analogue adaptive RF cancellation technique is introduced. It bases on the principle that the sum of two vectors with equal magnitude and reverse phase equals to zero. The leakage is decompounded into I-channel and Q-channel signals by millimeter wave(MMW) demodulator, I-channel and Q-channel signals are filtered and amplified, then the opposite vector of the leakage is constructed by MMW vector modulator. Finally, the constructed vector is coupled into the receiver to cancel the leakage. By adopting this method, a complete front-end demonstrator is developed.Test result shows that the leakage can be cancelled for more than 25 dB over 600 MHz, and the maximal value is 35 dB.