General properties of multistage bandpass filters with antiparallel configuration

This paper features the theoretical analysis of higher-order filters obtained by the cascading of the identical basic filters with antiparallel configuration. The analysis demonstrated that two possible general topologies of multistage filters have identical electrical characteristics but different practical applicability. An iterative formula for frequency characteristics calculation as well as formulas for the frequency position of transmission zeros and poles are developed. The employment of the formulas with a program for electric circuits' simulation could give educational models for analysis and designing of this filter type at various microwave frequencies.