Mathematical synthesis and design of third order Chebyshev combline band-pass filters with tunable topology

Abstract

A third order Chebychev combline band-pass filter topology is presented along with explicit design equations and circuit transformations for n-th order combline filter designs. The presented design operates at a center frequency of 2.45GHzand is easily tuned to center frequencies within ten percent of the filter's bandwidth. The presented design is the foundation for implementinga digitally tunable combline filter.