This paper presents a 0.4-to-6-GHz common receiver module for multi-band passive radar systems. In order to improve the anti-interference ability of the passive radar receiver, a super-heterodyne architecture with two optional channel bandwidths is proposed, which was realized by film bulk acoustic resonator (FBAR) filters for narrowband application and integrated low temperature co-fired ceramic (LTCC) filters for wideband application. The prototype of the common receiver module with a size of $\boldsymbol{22 \times 15\times 3 \text{mm}^{2}}$ has been designed and fabricated based on LTCC process. The test results show that the two optional channel bandwidths of the receiver are 65 MHz and 447 MHz. The total gain is no less than −9 dB and the gain flatness is 4.5 dB from 400 MHz to 6 GHz. The output 1-dB compression point $\boldsymbol{(\mathrm{P}_{-1\text{dB}})}$ is around 5 dBm. The common receiver module can be used for passive radar systems covering P-, L-, S- and C-band.