Quarter-mode substrate integrated waveguide

Quarter-mode substrate integrated waveguide (QMSIW) resonator, which is an isosceles right triangular microstrip patch loaded with an array of metallic via-holes along its hypotenuse, is discussed in this paper. Different kinds of inter-resonator coupling is studied, and coupling configurations are proposed. And then, a cross-coupled trisection bandpass filter and compact circularly polarized antenna are designed by using QMSIW resonator. The characteristics of the designed filter and antenna are studied. The results demonstrate that the proposed QMSIW structure is an excellent candidate for designing compact trisection filters which exhibits the asymmetric frequency characteristics and planar compact antenna with circularly polarized radiation property.