MICROWAVE FILTER DESIGN

1
MICROWAVE FILTER DESIGN
Melissa Ness Supervisor Dr. Marek Bialkowski
Filters are an essential part of
telecommunications and radar systems and are key
items in the performance and cost of such
systems, especially in the increasingly congested
spectrum. There has been a particularly marked
growth in the cellular communications industry in
recent years. This has contributed to both very
demanding performance specifications for filters
and the commercial pressures for low cost, high
volume and quick delivery. Through an
investigation into and a subsequent
implementation of filter theory, the techniques
to produce optimal filter performance for a class
of filters are developed in this thesis.
The core of this thesis has been the development
of an exact circuit synthesis, so that filter
design is not restricted to more conventional
responses. This has required an investigation of
the basic filter theory through to the
development of a generalised synthesis program.
Ultimately, the complex mathematical equations
programmed, which describe the filter function
are realised by a physical filter network. A
physical filter has been designed to
specifications, using the program developed.
This filter has been tuned and the responses
obtained are shown in Figures 2,3 and 4. The
practical results verify the integrity of the
whole process for efficient and elegant design of
filters, to meet stringent specifications. The
program uses the concept of a coupling matrix
representation for generalised Chebyshev
filtering functions
PHOTO TAKEN OF THE PHYSICAL FILTER DESIGNED USING
THE METHODS IMPLEMENTED IN THE THESIS