Design of combline and interdigital filters with tapped-line input

Explicit design equations for combline and interdigital filters with tapped-line inputs are presented. The equations are based on an equivalent circuit for a tapped-line input filter, derived from the open-wire-line equivalent circuit given by E.G. Cristal (ibid., vol.23, no.12, p.1007-113, 1975). Using the new equivalent circuit, explicit expressions are given for all parameters of the circuit. The design equations are checked by an analysis program. The results are compared to the data given by M. Dishal (ibid., vol.13, no.9, p.696-8, 1965) and E.G. Cristal