Parallel Coupled Bandpass Filter with Improved Filter Characteristics

This paper presents parallel-coupled bandpass filter using three rectangular shaped defected ground structure (DGS) with center frequency of 3.2GHz and bandwidth of 187 MHz. The designed filter performs better than the first coupled micro-strip filter [6] by modifying the resonators length, substrate thickness and employing DGS. The prototype filter simulated shows an insertion loss of -0.13 dB and return loss of -35.38 dB centered at 3.2GHz.The designed filter has the benefits of low insertion loss which can be used for modern wireless communications application like WiMAX.