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Here, a compact balanced bandpass filter (BPF) with high selectivity and good common‐mode (CM) suppression is proposed by adopting the TM dual‐mode substrate integrated waveguide (SIW) cavity. The SIW cavity is connected to the input and output by the way of microstrip‐slotline transition. Under differential‐mode (DM) operation, two TM modes (TM120, TM210) of the SIW cavity can be effectively excited, and simultaneously two transmission zeros (TZs) can be generated near the passband edges. Meanwhile, by designing the rotation angle and size of coupling slots reasonably, the deep stopband performance can be realised over a wide frequency range. Furthermore, the CM signal is effectively rejected because the magnetic current cannot be transferred to the coupling slot from the virtual open‐ended microstrip feedline. Finally, a compact balanced BPF prototype for WLAN application has been designed and fabricated. Good agreement between simulated and measured results is obtained.