Triple Band Filter with Cross Coupled SIR for Wireless Applications and Harmonic pass band Rejection with DGS

A triple pass band filter is proposed for wireless applications. Four cross coupled Stepped Impedance Resonators are used for the purpose. Three pass bands at 2.4, 3.5 and 5.4 GHz are achieved. Minimum Insertion Loss of the three pass bands are 1.00, -0.52 and -0.92 dB respectively. The Return Loss in the said pass bands are -27,-21 and -22 dB. The overall size of the designed filter is 24.7 mm x 18 mm (0.19 $\lambda_{g}$ x 0.14 $\lambda_{g}$). The Defective Ground Surface is introduced in the design to reduce the spurious pass bands and hence to improve the pass band selectivity and stop band suppressions.