Links to rf & microwave filter design related websites

1. Filter Synthesis

A very versatile filter- and network synthesis tool from Professor N. Yildirim of Turkey. Classic LC synthesis, commensurate line filter synthesis and all network transformations under the sky are concentrated in this unique software tool. Narrowband filters using cascaded triplets and quadruplets are fully covered. I had the pleasure of being involved in its creation. There is a comprehensive manual available for download.

Featuring very useful & advanced filter synthesis & design software including diplexer and filter  multiplexer design. Many aspects, like power handling and altitude effect are covered.

A fresh approach to coupling matrix synthesis from Switzerland. Covers narrow bandpass approximation, transfer function and coupling matrix synthesis.

ELSIE is a useful lumped element filter design software for students and engineers. Well written and easy to use. Covers many topology alternatives and analysis formats. The student version if free to download.

A fine  online tool for filter design from Denmark. Covers advanced filter topologies as well as in-depth filter analysis. The software is also available for download.

Dedale-HF – scientific webpages for filter synthesis by Fabien Seyfert of INRIA (French Research Institute). Very educative and comprehensive. Matlab code based software can be downloaded.

Two  classic  filter synthesis tools by one of the grand masters of filter design. Derived from previous DOS versions.

IEEE MTT-8 Archives – classic filter papers

Categorized lists of classic filter papers published in IEEE MTT. Not complete, but very useful.

Software for combline filter design and specialized software for filter optimisation using AWR MWO and customised training classes for high-Q TEM-mode filter design, planar filter design and filter design using SMT.

RF and many other filter design info, including downloadable software.

2. 3D Electromagnetic Analysis

Leading scientific 3D electromagnetic analysis tool from Germany. Offers both time domain and frequency domain solvers as well as eigenmode analysis. Many useful application notes and seminar presentations on filter design and realisation. Integrated circuit analysis tool for co-simulation.

HFSS – high frequency structure simulator. Classic frequency domain and eigenmode solver. Previously offered from both Agilent and Ansoft. Now part of the Ansys software suite. Circuit simulation via Ansoft Designer links to HFSS 3D simulation. Claims for being an industry standard are perhaps no longer valid.

The fast mode-matching 3D simulator from Germany. Well suited for many filter types, including waveguide resonator filters.

3. Network Analysis

Agilent ADS – Advanced Design System

Born out of the EESof Touchstone circuit simulator, ADS offers a whole world of simulations. Loaded with features including electromagnetic simulation. Probably the best tool – if you can afford it 🙂 I still use an older version for my simulations and I would not want to do without it.

AWR – Microwave Office

Innovation in circuit simulation. A real microwave design platform. Very good user interface and clear cut structures. A permanent tool on my PC. The ready-made filter block models, especially the General Chebyshev Filter block is indeed very useful for easy simulation and design work. The gradient optimiser took a long time to mature but is quite good now. I usually use gradient optimisation and still find it a bit slow. If you need nodal voltage analysis there is some bad news: AWR – most unfortunately – package linear nodal (AC) analysis within their non-linear ‘harmonic balance’ option. The cost for this is significant and unjustifiable if all you need is linear AC nodal analysis for finding internal voltages. There is of course an easy workaround if you are happy with normalised voltages.

Ansoft Designer

The Ansoft way of circuit simulation. Links nicely to Ansoft HFSS enabling concurrent EM- and circuit simulation as well as co-simulation.


Handy and very useful free circuit simulator. Downloadable from various websites. I sometimes use it to view .SnP files.


Quite useful circuit simulator – indeed, it is. Offers many features only found in commercially available packages.Even optimisation can be included via an add-on feature. Includes a fine filter synthesis tool for standard filter responses, like Chebyshev, Butterworth, Cauer and Bessel.


This low-cost vector network analyser is indeed outstandingly good. A friend has bought one and I have seen it in action. This unit brings network analysis to those who could not afford buying network analysers. A game changer I would say! Also a very good tool for universities. Impedance measurement accuracy is probably a bit limited, but up to 25 dB return loss levels it is pretty good.

4. Academic Links

Professor Ming Yu of Waterloo University in Canada is both a high-class academic as well as an experienced industry R&D expert. His website is very resourceful. His pioneering work on computer-aided-tuning of filters ( CAT ) is of special importance.

I am privileged by his endorsement of my work on microwave lowpass filter design.

Among professor Bandler’s major contributions is the concept of ‘space mapping’ where the variables of one simulation domain are linked to those of another. For example 3d em simulation linked to circuit simulation. This concept opens up a powerful method for the design of passive and also active microwave structures. I had the honour of being invited to speak at his 2002 IEEE IMS workshop in Seattle (Link to 2002 presentation).

5. Other

A good attempt at providing condensed information on filter design by K. V. Puglia.

List of filter design related pages at


A fine software for transforming  measured frequency domain S-parameter data (eg. S11) into time domain for various purposes, including locating reflections on a transmission line feeder. Well suited for antenna feeder performance analysis and fault location.


Online resource for hardware engineers with forums, articles, tools, projects. Covers analog design, rf design, power management, embedded design, test & measure, components and pcb design.


The NEC wire antenna analysis software was originally developed by the Lawrence Livermore National Laboratory in the 1970s. 4NEC2 is a fine Windows version, easy to use and has all desirable features of an antenna analysis simulation program.