Planar UWB-bandpass filter with multiple passband transmission zeros

A planar ultra-wideband (UWB) bandpass filter (BPF) with multiple passband transmission zeros (TZs) and wide stopband is reported in this manuscript. The basic architecture of the BPF consists of two microstrip-to-coplanar waveguide (CPW) transition arranged on either sides of the substrate. A 3rd order BPF hence developed displays good frequency characteristics with two TZs on either passband edges. Later, defected ground structures (DGS) in the form of complementary split ring resonator (CSRR) and complementary folded split ring resonator (CFSRR) are utilized to place three TZs in the passband so as to cut off in-band interferences. Upon optimized simulation, a prototype is eventually developed and measured for compatible frequency characteristics.