In this letter, a simple approach for design and realization of dual mode substrate integrated waveguide (SIW) bandpass filter of order higher than two is presented. The dual mode resonators are square SIW cavities perturbed by corner cut perturbation. In the coupling configuration of the proposed filter, the odd and even modes of the perturbed cavities are used as basis modes. Different paths are provided for the odd modes and the even modes from input to output port and, therefore, the sensitivity of filter with respect to the fabrication tolerance is reduced. Using this approach, a fourth-order dual mode bandpass filter is designed and realized and a filter prototype is fabricated on a single layer substrate using PCB technology. The measured results are in a good agreement with the simulated results.

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