An Integrated Substrate Gap Waveguide Wideband Filter for 5G Millimeter Wave Application

In this paper, an Integrated Substrate Gap Waveguide (ISGW) planar broadband bandpass filter that can be applied to the 5G millimeter wave N257 and N258 bands is proposed, and good filtering characteristics are obtained at the lower resistance band by introducing circular patches on the strip line of the ISGW. Then radial-shaped slots are cut on the circular patch and a defective ground structure is introduced on the upper surface to achieve better filtering performance. The filter has good filtering effect, low group delay and miniaturization characteristics. Simulation results show that the filter can achieve S11<-10 dB in the range of 22.99 ~ 28.67 GHz, the overall in-band group delay is less than 0.5 ns, the 3 dB fractional bandwidth (FBW) reaches 20.56%, and two radiation zeros are introduced on each side of the passband to achieve better out-of-band rejection.