SIW Cavity Mode Analysis and Control Techniques for Compact Wide-Stopband Filters Design
Daotong Li, Wei Luo, Xiaoquan Chen, Jiaxin Wang, Chen Yang, Kai‐Da Xu, Qiang Chen
Abstract
In this paper, a compact novel type of wide-stopband bandpass filter (BPF) is presented based on perturbed dual-mode substrate integrated waveguide (SIW) cavity. The perturbed metallic vias are introduced at the center of SIW cavity to achieve a dual-mode SIW cavity by shifting the resonant frequency of TE101 mode toward TE201 mode. Moreover, by setting the external ports to the positions at electric field nulls of the high order spurious modes, the wide-stopband BPF can be realized. Through suppressing the unwanted modes, which includes at least seven modes, the widest stopband up to 2f0 can be obtained in a single SIW cavity. To verify the proposed wide-stopband filter, two prototypes are designed, fabricated and measured, following the stopbands of 2f0 with the rejection level better than 20dB and 30dB, respectively.