Trisection bandpass filter based on quarter-mode substrat integrated waveguide

This paper presents a microwave bandpass filter using a triplet configuration to realize cross coupling. A structure called quarter-mode substrate integrated waveguide (QMSIW) is applied in these resonators to achieve the planar form. QMSIW is an isosceles right triangular microstrip patch loaded with an array of metallic via-holes along its hypotenuse which can be equivalent as an electric wall and the other two edges are equal to magnetic walls. The filter was simulated and fabricated at the center of 2.35GHz with a bandwidth of 330 MHz and good agreement was achieved between the simulated results and those measured.