Course #10
RF and Microwave Filter Design with EM Simulation
We recommend you to submit your
preliminary or firm registration at least 4 weeks before course
start to ensure a seat on the course.
New date to be
decided
TECHNOLOGY FOCUS
Filters are one of the fundamental building blocks of RF
and microwave systems, along with amplifiers, oscillators, mixers,
and switches. Filter design and realization can be challenging for
several reasons. No one technology or filter topology is suitable
for all applications. There is also a fundamental limitation
imposed by the relationship between unloaded Q and
volume.
Many of the simpler design procedures can sometimes arrive at
geometries that are unrealizable, and the available literature is
generally focused on theory rather than practical information on
realization. However, with a few basic concepts in hand, even the
non-specialist can achieve useful results.
Electro-Magnetic (EM) simulation is also an essential component of
modern filter design.We now have the ability to model and optimize
complete filter structures in the EM domain. Current developments
in cluster computing and multi-threading promise to enhance those
capabilities as well.
COURSE CONTENT
This course is devoted to the fundamentals of practical
filter design for RF and microwave systems.The core material is a
universal procedure for narrow band filter design that can be
applied to virtually any filter technology or topology. The
procedure is rooted in Dishal's method with powerful extensions
that include the port tuning concept, equal ripple optimization
techniques, and efficient EM simulation. All the techniques
presented can be implemented using commercially available CAD
tools.
Practical procedures for extracting unloaded Q, external Q, and
coupling coefficients are quite important in the design process and
in evaluating prototypes. These techniques will include extracting
data from hardware and from EM simulations. Some tutorial material
on field-solvers will also be presented. The EM simulation examples
relate specifically to filter design and include tips and
techniques for more accurate and efficient simulation.
Example filter designs that cover a broad range of commercial and
military applications will be presented with measured data and
error analysis.The instructor will choose examples to develop based
on the interests of the class. The course material is suitable for
filter designers, designers of other components, systems engineers,
and technical managers.
Monday
Filter Design, Optimization, and Port
Tuning
We will present the briefest possible introduction to
basic filter design concepts. Starting with lowpass prototypes, we
will touch on Chebyshev and elliptic prototypes and finding
prototype element values. Next we will turn to a brief overview of
the most common filter design techniques. Topics will include
synthesis from an insertion or return loss function, the coupling
matrix approach, and synthesis by optimization. The use of general
purpose linear simulators for equalripple optimization will also be
discussed. Finally, we will introduce the port tuning concept.
- Basic Filter Concepts
- Chebyshev and Elliptic Prototypes
- Synthesis From Insertion Loss Functions
- Coupling Matrix Approach
- Synthesis by Optimization
- Equal-ripple Optimization
- The Port Tuning Concept
Tuesday
Narrow Band Filter Design and EM Simulation
Our approach to narrow band filter design starts with
Dishal's method and moves a step beyond with port tuning of a full
EM model. The port tuned model is a virtual prototype that can be
diagnosed and optimized before any hardware is built. Modern TEM
filters often employ cascade triplets and quads to realize
transmission zeros in the stopband or flatten group delay in the
passband. These filters can also be designed using our approach. At
some point, practical
procedures are needed to measure unloaded Q, external Q, and
coupling coefficients. Systematic methods for tuning filters are
also needed. All of these methods and procedures can be applied to
actual hardware or to an EM simulation of the hardware.
- Narrow Band Filter Design
- EM Filter Prototypes
- Cascade Triplets and Quads
- Unloaded Q
- External Q
- Coupling Coefficients
- Filter Tuning
Wednesday
Designing Combline, Waveguide, DR Filters, and
Diplexers
When higher unloaded Q is required, designers often turn
to cavity combline, waveguide, or dielectric resonator (DR)
filters. Combline and DR filters are now used in high volumes in
cell phone base stations. Meeting customer requirements often
requires additional transmission zeros in the stopbands, which are
realized using various types of cross-couplings. Both narrow band
and broadband combline filters can be found in many military
systems. Some applications also call for these high performance
filters to be diplexed or multiplexed. Again, strategies for
efficient design and EM simulation will be discussed for all the
topologies presented.
- Cavity Combline
- Waveguide
- Dielectric Resonator
- Base Station Filters
- Diplexers and Multiplexers
- Strategies for Design and EM Simulation
Thursday
Designing Planar Filters
Filters in planar form can be built using several
different topologies and technologies. Various single and
multilayer ceramic and soft substrate (PCB) technologies are
available to the filter designer. We will cover the more common
distributed topologies including edge-coupled, hairpin, and
interdigital. More recent coupled and cross-coupled loop topologies
will also be presented. At lower microwave frequencies a
pseudo-lumped approach using printed inductors and capacitors is
more space efficient. Lowpass, elliptic lowpass, and bandpass
filters using this approach will be presented. Strategies for
efficient design and EM simulation will be discussed for all the
topologies presented.
- Planar Filters
- Single and Multilayer
- Ceramic and PCB
- Edge-coupled, Hairpin, and Interdigital
- Coupled and Cross-coupled Loops
- Pseudo-lumped Lowpass and Bandpass
- Strategies for Design and EM Simulation

Said about the course from previous participants:
"The course has an engineering approach and the teacher
gives many examples and explains mistakes also."
"Broad coverage of filter designs and different
technologies."
"Pointers on how to dig deeper into certain aspect."
"Lots of measurement results."
"A good coaching of all aspects. Industry relevant and practical
experienced teacher."
"Fits my work very well, working as a filter designer. Best course
I have been to!!!"
"Very related to real problems. Touch different technologies with
a good approach to actual designs."
"State-of-the-art lecture material."
"Practical hints and tricks."