A novel substrate integrated waveguide (SIW) based highly selective filter for radar applications

In this paper, a novel Substrate Integrated Waveguide (SIW) based narrow bandpass filter is presented. In the proposed design, filtering response is achieved by inserting inductive posts in the SIW structure. Simulation of the proposed structure is carried out using commercial software Ansoft High Frequency Structure Simulator (HFSS), which is a three-dimensional full wave solver utilizing the finite element method (FEM). The proposed filter is fabricated on the dielectric material RT duroid 5880 with the dielectric constant ϵr = 2.2, dissipation factor tanδ = 4 × 10−4 and height h = 0.508 mm. The measured insertion and return losses are 1.22 and 18.34 dB, respectively. The measured 3-dB fractional bandwidth (FBW) is 1.475% at the center frequency of 12.2 GHz.