Area-Efficient Non-Uniform Lowpass Filter Design

Design and implementation of area-efficient nonuniform lowpass filter based on planar circuit method (PCM) is presented. More specifically, segmentation method is used alongside Green's function method in order to design multi-section transmission line lowpass filters in minimum given area, while achieving superior results compared to conventional techniques based on quasi-lumped elements. Analysis and procedure outlined here lay the foundation for PCM-based synthesis and systematic design of multi-section non-uniform TL LPFs. Results obtained from analysis, full-wave simulations and measurements all confirm the validity and accuracy of the presented approach, which no doubt can offer extra flexibility and freedom in design of similar microwave filters as well as other more complex planar circuits.