LAUSR

Abstract In this paper, a combination of slot ring and complementary split ring resonators has been proposed to achieve quad band bandpass filter response in waveguide. The resonators have been formed on a Roger RO 4350 substrate with their common centre at the middle of the substrate. Two such structures have been placed on the transverse plane of a WR–90 waveguide at a distance of 8.41 mm to achieve the dual pole quad band response. Necessary simulations have been carried out using Ansoft HFSS (version 14). Measured result shows a quad band bandpass response with centre frequencies at 8.51/9.46/10.47/12.05 GHz and 3-dB bandwidth 0.256/0.2287/0.445/0.755 GHz, respectively. Approximate equivalent circuit of the filter is also proposed. The filter is 10 mm long.