Design and Realization of Novel RF Bandpass Filter Using Short-circuited Coupling Element

In this paper, a development of novel microstrip bandpass filter (BPF) structure is presented using simple lumped element circuit composed from four capacitors and inductance transformer. The design of BPF is based on mathematical modelling of mentioned lumped element circuit and its transformation to planar components determined by transmission line theory. The correctness of proposed technique is demonstrated on practically realized microstrip BPF with center frequency set to 820MHz and -3dB bandwidth of 50MHz.