In this paper, a novel high-order triple-mode half-mode bandpass filter using a single perturbed substrate integrated waveguide (SIW) cavity and a dual-band diplexer are presented. Circular shape metal via-holes are added in the middle of a square SIW cavity as perturbation. The perturbed TE101, TE102 and TE201 resonant modes of the SIW cubic cavity are used to design the proposed filters, which can be shifted to the desired frequency by adjusting the position and size of via-holes. The proposed method reduces the size of the filter, and the measured results indicate that the bandwidth is higher than previous literatures. The dual-band diplexer with a half-mode SIW (HMSIW) structure can be easily implemented based on the proposed BPF through a T-junction, which decreases the number of resonating elements. A triple-mode half-mode filter using a single perturbed SIW cavity with center frequency of 7.43 GHz is obtained. The designed filter and dual-band diplexer are fabricated and measured to validate the present approach.
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