A compact broadside coupled dual notched band UWB-BPF with extended stopband

This manuscript describes a compact multi notched band ultrawide band (UWB) bandpass filter (BPF) based on broadside coupling of microstrip and co-planar waveguide (CPW). Initially, a meandered CPW embedded in ground plane is optimized efficiently to allocate the resonant modes equi-spaced within the UWB passband (3.1-10.6 GHz) and later, the tight coupling of the transition of microstrip with the CPW ensures a smooth passband. Four open ended stubs are appended with the microstrip patches on top to attenuate dual passband frequencies and improve higher stopband performance. An approximate equivalent circuit model of the prototype is developed and its circuit response is compared with full wave EM simulation data. The compact prototype measures only 13 x 7 mm(2).