Abstract: 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.