Study of a fifth order synthesized combline filter for a self-structuring filter prototype

This work presents the study of a 5 GHz synthesized Chebyshev combline filter and its potential use in a self-structuring filter prototype. The self-structuring filter prototype will be a system where the center frequency and bandwidth can be controlled by an algorithm to produce the desired bandpass filter response. The impact of tuning capacitances on the insertion loss, 3 dB bandwidth and percent bandwidth of a combline topology with tapped input/output resonators was determined using linear and electromagnetic (EM) simulations. Linear simulations show that the center frequency can be tuned from 3.7 to 6.4 GHz using the static capacitance values of 1.24 to 0.31 pF for the SMV1430-079LF varactor.