<p>Passive bistatic radar (PBR) exploits illuminators of opportunity such as frequency-modulated (FM) radio and cellular base stations, providing low-cost and resilient sensing. Reliable detection requires a clean reference signal; however, target echoes may leak into the reference channel due to wide antenna beamwidth, geometry, or target motion. Such contamination generates ghost peaks in the range-Doppler plane that share the true target’s Doppler but are shifted in range, making them difficult to separate and severely degrading detection. This paper analyzes the mechanism of ghost-peak formation from a matched-filter perspective and proposes a suppression strategy that combines multi-frame consistency analysis with an anchor-based masking operation. Unlike reconstruction-based methods, the proposed approach applies lightweight post-detection processing to selectively remove spurious responses while preserving genuine targets. Simulation studies using synthesized data derived from measured FM broadcasts demonstrate that the method effectively suppresses ghost peaks across different contamination scenarios, reduces false tracks, and maintains reliable detection with low computational cost. These results confirm the practicality and efficiency of the proposed approach for mitigating target-induced contamination in passive radar.</p>