Analysis and Design of Substrate Integrated Waveguide Bandpass Filter for 5G Applications

This paper presents the analysis and design of a fourth-order substrate integrated waveguide (SIW) bandpass filter. The designed bandpass filter operates in the frequency range from 3.7 GHz to 3.98 GHz which covers the New C-band 5G network with fractional bandwidth (FBW) of 28% and centered at 3.84 GHz. The design procedures of bandpass characteristics are summarized by calculating the external quality factor and the coupling coefficients from the physical structure. The presented design is based on three direct inductive coupling between four arranged SIW cavity resonators and only one cross-coupling between the resonators at the input and output ports. This fourth-order bandpass filter is synthesized, designed, fabricated, and measured. Good agreement is achieved between the measured and the simulated results.