Bandpass filter microstrip using octagonal shape for S-band radar

In this paper, the simulation and realization of Bandpass filter with octagonal shaped hairpin have been done to investigate dimention and filter responses. This filter is designed with open loop resonators and the half wavelength octagonal. Bandpass filters are made in the form of microstrip line filter using fully groundplane at the button of the substrate with a center frequency is 3 GHz. Microstrip line is a transmission line consisting of strip conductors (patch) and groundplane separated by substrate with certain material characteristics. Patch and groundplane used comes from the copper layer, substrate having a 4350B Rogers Duroid epsilon equal with 3.48 and the value of the loss tangent of 0.0004. The design created with Advanced Design System software 2011 and the optimization up to get the value of the desired specifications. Then, printed with etching process. The result of the measurement for return loss is −24.12 dB, Insertion loss is −1.5 dB with the 340 MHz bandwidth.