基于平衡式反射型调制器的反射功率对消器

基于模拟最小均方(analogue least mean square,ALMS)环路的反射功率对消器能够自适应地抑制载波干扰,故常应用于连续波雷达中。传统的反射功率对消器使用基于矢量调制器的独立馈通电路产生对消信号,对消电路复杂度高。提出一种改进的反射功率对消器,对消器使用一个平衡式反射型正交调制器产生对消信号,避免了独立馈通电路的使用,从而简化了电路结构。平衡式的正交调制器具有较好的I/Q平衡性,确保ALMS控制环路在较宽的频带内保持稳定。最终制作了工作在UHF 频段的对消器模块。测量结果显示,该模块对以915 MHz为中心频率、带宽60 MHz的线性调频干扰信号具有良好的自适应跟踪能力。在干扰功率+10 dBm 条件下,典型的等效输入噪声谱密度为-153 dBm/ Hz@100 kHz。

A Reflected Power Canceller Based on Balanced Reflective Modulator

Analogue least mean square (ALMS) loop based reflected power canceller (RPC) is capable of adaptively suppressing carrier leakages in continuous-wave (CW) radars. A feedthrough circuit which utilizes a vector modulator and generates cancelling signal is generally implemented in a traditional RPC, which leads to a considerably complex circuit design. In this letter, an improved RPC, which utilizes a balanced quadrature reflective modulator, is proposed. Independent feedthrough circuits are eliminated and the canceller circuit can be greatly simplified. Furthermore, the balanced quadrature reflective modulator offers low I/Q imbalance, which ensures the wideband stability of the ALMS control loop. A UHF band prototype of the proposed canceller is fabricated and measured. The prototype demonstrates its ability to adaptively track a linear FMCW leakage with a bandwidth of 60 MHz centred at 915 MHz. Typical input-referred noise power spectrum density is -153 dBm/ Hz @100 kHz offset and +10 dBm leakage level.