Analytical synthesis algorithm of dual-band filters with asymmetric pass bands and generalized topology

A straightforward method for the synthesis of dual-passband filters is proposed. The method reduces the synthesis algorithm to the computation of only two coefficients, that completely determine the dual-band response as long as it is adequately normalized in frequency. The resulting network is built by attaching an additional resonator to each existing one, being all the new resonators identical. This kind of coupling matrix is a suitable model for edge-coupled split-ring resonator filters, as a dual-band GSM-1800/IEEE 802.11g prototype with transmission zeros shows.