Folded waveguide resonator filter for communication and radar systems
Abstract
In this thesis, a primary investigation into developing a compact and low-loss bandpass
filter, using novel folded waveguide resonators with a footprint reduction, has been
addressed. A slot coupling between adjacent resonators is introduced, which is
characterized by using full-wave EM simulations and verified experimentally. Two
designs of 2-pole folded waveguide resonator filters of this type have been considered,
fabricated and tested. In this thesis, an even more compact FWG resonator filter using a
novel slot technique is reported. The attainable size reduction is about 50%, and the
filter design is based on theoretical and full-wave electromagnetic (EM) simulations.
Based on FWG structure, two types of folded waveguide resonators have been studied
and considered the half-wavelength resonator and the quarter-wavelength resonator.
Moreover, both structures for the realization of microwave cavities with high-Q, with
the result of a high spurious free range and reduced footprint, have been evaluated.
Furthermore, a novel folded waveguide resonator with about a 75 % reduction of the
volume from the conventional size has been described. For comparison, two types of
folded waveguide resonators have been studied, i.e. the quarter-wavelength resonator of
square shape and the newly proposed triangular shape. In addition, a demonstration of a
filter application for miniature triangular folded waveguide resonators has been
designed and simulated using an EM simulator.
In addition, numbers of experiments have been conducted to develop cavity FWG and
Substrate Integrated folded waveguide SIFW resonator filters using a folded structure,
which is the main aim of this thesis. Furthermore, this thesis deals with the simulation
and implementation for many designs and topologies of FWG and SIFW resonator
filters and their frequency response. Simulation and experimental results were presented
to validate the design and to show the advantages of these types of filters. In addition, a
new type of filter with a compact multi-layer structure and low loss is attractive for
implementation with advanced device technologies, such as micromachining, LTCC
and LCP technologies.