Abstract: The Wi-Fi signal can be used as an illuminators of opportunity for passive radar to detect moving targets at close range, but owing to its limited bandwidth, the range resolution is often difficult to meet the practical requirements. In this paper, a method is present to broaden signal bandwidth by using multiple different channels of Wi-Fi signals spectrum shifting, the phase inconsistency between signals in practical applications and its influence on the detection performance of synthetic signals are analyzed theoretically, and a compensation method is proposed. The proposed method can improve not only the range resolution, but also the output signal noise ratio after matched filtering. The performance of the proposed method is proven by computer simulations.