Compact dual-band SIW filters loaded with double ring D-shaped resonators for sub-6 GHz applications

Abstract

In this paper, a compact substrate integrated waveguide (SIW) based dual-band filter which utilizes the dual resonance provided by asymmetric double-ring D-shaped resonators that are incorporated on the upper metallic layer of SIW is communicated. The two passbands are generated well below the cut-off frequency of the SIW due to evanescent mode propagation. Such propagation is responsible for the substantial miniaturization of the filter as well. Two types of two-pole dual-band filters are designed that exhibit low insertion loss, wide out-of-band-rejection, compact size, easy fabrication and integration with other microwave components. To validate the proposed idea, three filter prototypes working around 2.66 and 3.54 GHz are designed, fabricated for demonstration and experimentally tested. Parametric analysis is performed to verify the dependence of filter parameters on the proposed filter prototype. Expected agreements are achieved between the experimental and simulated results. The proposed filter finds applications in the upcoming 5G sub-6 GHz communication.