Novel half-mode substrate integrated waveguide filters with modified broadside-coupled split ring resonators

Novel half-mode substrate integrated waveguide (HMSIW) bandpass filters with modified broadside-coupled complementary split ring resonators (MBC-CSRRs) are presented in this paper. The unit cell of the HMSIW with the MBC-CSRR is investigated firstly. It is shown that the MBC-CSRR demonstrates a better stopband performance compared to the conventional BC-CSRR, while keeping the main advantages of the BC-CSRR such as achieving a compact size conveniently by using thin dielectric substrate. HMSIW bandpass filters with the MBC-CSRR are designed, fabricated and tested. The measurements agree well with the simulations. The proposed filters show a good stopband performance with a broad rejection band, and they are compact, low loss, low cost and easy to integrate with other circuits and components.