Prototype network synthesis for wideband microwave filters

Summary form only given, as follows. A direct synthesis method is presented for a folded bandpass filter prototype network. The prototype network consists of LC resonators coupled by frequency-dependent couplings, which model the filter responses over a wide frequency band. Commencing from transfer and reflection polynomials, a two-port [ABCD] transfer matrix is formed, enabling the extraction of variant circuit elements from input and output ports of the prototype network.