Dual-Band Bandpass Filter Using Dual-Mode Square SIW Cavities with Controllable Center Frequencies and Bandwidths

This paper introduces the design of dual-band bandpass filters (DBPFs) based on dual-mode square SIW cavities for Ku-band applications. The dual passbands are generated by exciting the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{101}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{201}$</tex> modes within the cavity. Metallic vias are introduced into the SIW cavity to perturb the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TE}_{101}$</tex> mode and adjust its center frequency. To enhance passband selectivity, source-load coupling technique is applied into the filter structure. The proposed DBPF offer independent controllability of center frequencies and bandwidth with tunable design parameters. The full-wave electromagnetic simulations are performed using Ansys HFSS. The filter operates at 13.3 GHz and 15.3 GHz with fractional bandwidths of 1.5 % and 1.3 %, insertion losses of 0.64 dB and 0.82 dB, and return losses above 18 dB at both center frequencies.