General coupled resonator filters design based on canonical asymmetric building blocks

A new principle of generalized coupled resonator filter is proposed for multiple transmission zeros realization. For low order filters, the canonical filter prototype is feasible for both symmetric and asymmetric transmission zeros implementations. The general canonical filter configuration and the corresponding response are summarized for filter order less than or equal 5. For high order filters, the cascading of canonical asymmetric building blocks is proposed for either symmetric or asymmetric filters. Design examples are presented to demonstrate the principle.