Generalized Coupling Coefficient for Filters With Nonresonant Nodes

In this letter, we introduce a generalization of the coupling coefficient definition that applies to filters, including nonresonating nodes. The novel coefficients are evaluated from the synthesized low-pass prototype (suitable formulas are given); they allow an easier prototype de-normalization because no complicated network transformation is requested. Several different solutions with preassigned network parameters can be easily obtained by exploiting the degree of freedom offered by the de-normalized network. Some examples illustrating the use of the new coefficient are given.