A non-contact phase-locked and self-injection-locked vital sign sensor is disclosed. The non-contact phase-locked and self-injection-locked vital sign sensor includes a self-oscillating voltage-controlled frequency adjustable radiating element, and a phase-locked-loop. Compared output signal of self-oscillating radiating element with a reference signal by phase-locked-loop, and produce a tuned voltage, which tunes the oscillation frequency of the self-oscillating radiating element to the setting frequency, according to comparison output to maintain the same phase relationship between oscillation signal and reference signal. So as to stabilize the oscillation frequency and increase measurement sensitivity by phase locked loop.一種非接觸式相位鎖定暨自我注入鎖定生理信號感測器，其包含一自我振盪壓控輻射元件以及一鎖相迴路。由鎖相迴路將自我振盪壓控輻射元件輸出之除頻後之振盪信號與一參考信號進行比對，根據比對結果產生一調控電壓，用以將自我振盪壓控輻射元件之振盪頻率調回設定值，使振盪信號與參考信號保持相同相位關係，該調控電壓即為生理信號。自我振盪壓控輻射元件則因使用鎖相迴路鎖住振盪頻率，而使頻率穩定，並提高感測靈敏度。
