A New Equivalent Circuit for Inverters and Its Application for the Determination of Coupling Matrix Elements of Narrow RF Bandpass Filters
A new equivalent circuit for inverters is presented. Using this circuit, expression for the elements of the coupling matrix of narrow RF band pass filters is derived. The derivation is based on frequency independent coupling assumed in the synthesis of narrow RF band pass filters. Our expression is different from an earlier expression obtained using lumped circuit representations of different types of coupling and their analysis. It is shown that the earlier expression can be derived from our analysis if the coupling is assumed frequency-variant. Unlike earlier work, our derivation shows how the sign of the coupling coefficient can be obtained. (c) 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE 20: 122-127,2010.
equivalent circuit inverter coupling matrix rf bandpass filter resonators