A Wide Band Bandpass Filter Using Floating Split Ring

Here in this paper a compact wideband bandpass filter (BPF) is presented. The size of the end coupled dual-resonator bandpass filter is reduced with a reasonably wide spacing between resonators. The broadside coupling provided by multi-layered structure is used to produce controllable transmission pole. The first unwanted harmonic is removed by introducing quarter wave resonators. For validation of the design a BPF centred at 2.49 GHz with a 3dB fractional bandwidth of 24% is designed, fabricated and measured. There is good agreement between simulated and measured results. The overall cut out size of the filter is 16x3mm².