volume | PIER Journals

Abstract

To increase the stopband width of the filter, a second-order wide-stopband substrate-integrated waveguide filter is suggested. This filter is designed by utilizing a DGS structure and the weakest electric field approach. To suppress the modes, the filter sets the inner and outer coupling windows at the modes' weakest electric fields (TE₁₂₀/TE₂₁₀, TE₂₂₀). Additionally, a new nested U-shaped DGS structure is implemented to suppress the TE₁₃₀ mode, hence expanding the stopband width of the filter. The filter has been processed and measured, and the findings indicate a 4.5 GHz center frequency, a -3 dB bandwidth of 240 MHz, a relative bandwidth of 5.3%, an insertion loss of -1.2 dB in the passband, and a -22 dB stopband, which can be extended up to 9.4 GHz (i.e., 2.1 times the center frequency). The simulated and measured results demonstrate good alignment. Compared to other SIW filters, the current filter achieves a wider stopband while using fewer orders and implementing a straightforward design method, providing potential value for applications.

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Dr. Yuxin Fang

Prof. Xiaohei Yan

Dr. Yixian Wang

Dr. Shengbing Zhang