Design of substrate integrated-waveguide wide stopband bandpass filter for 5G applications

In this brief, a wide stopband bandpass filter is designed based on the substrate integrated waveguide (SIW) coupling with complementary split ring resonators (CSRRs) and defect ground structure resonators. The proposed filter exhibits excellent roll-off and wide stopband characteristics with single SIW resonator cavity. A simple capacitive slot line is also proposed to improve the flatness in the passband. In order to verify the feasibility of this scheme, the filter is processed and measured. The measurement results show that the operating frequency band is 4.4GHz-5.0GHz which covers the N79 frequency band of 5G microwave communication with stopband range of 6.4GHz-21.6GHz.