Compact filtering power divider using mixed quarter‐ and eighth‐mode substrate integrated waveguide resonant cavities with flexible design

Abstract

In this paper, a series of filtering power dividers (FPDs) employing quarter‐mode substrate integrated waveguide (QMSIW) and eighth‐mode substrate integrated waveguide (EMSIW) resonant cavities have been first demonstrated. The proposed prototypes possess the merits of extremely miniaturized dimensions and relatively low insertion loss. Based on the detailed analysis and investigation of electromagnetic features and feeding types corresponding to the miniaturized SIW resonant cavities, two‐order mixed QMSIW and EMSIW FPDs with electric coupling or magnetic coupling topologies are presented. In addition, multi‐layered structures are implemented to decrease the footprints of the FPDs further. To attain a higher‐order design and enhance the out‐of‐band rejection, a four‐order multi‐layered FPD with cross coupling mechanism is finally developed. For demonstration and verification, seven prototypes of the proposed FPDs operating at 4.8 GHz are meticulously designed, fabricated, and measured. All experimental results are in reasonable agreement with the simulated ones.