Synthesis of Equally Terminated Low-Pass Lumped and Distributed Filters of Even Order (Correspondence)

A Chebyshev-like polynomial of even order is described which, when used in low-pass filter design of even order, allows for the output to input resistance ratio of the filters to be specified independently of the passband ripple level. This is an improvement on the conventional theory, which requires that the resistance ratio be a junction of the passband ripple level. In particular, the important case of equally terminated lumped and distributed lowpass filters is considered in detail, and tables of element values are given for a large number of practical design specifications.