cavity filter design

Hi friends ,

I am working on Cavity filters for more than one year(In testing & tunning) Now I want to Know the basic design steps and softwares best worked for the above. I tried HFSS and Zealand on working filters but unable to get the response as expected.

Thanks
Madhu

u can use ansoft designer and microwaveoffice .
they are friendly to be used for filter design.

Thanks for the reply.

I want to know is there any possibilty in Microwave office & ansoft Designer for 3D modelling as I find it only for microstrip strucutres.
As, I am dealing with Cavity type of filters such as Resonator Rods.


Madhu

I think you should use HFSS or CST for your cavity filter with resonant posts.
Good luck.

I have down a Ansoft Designer SV for it is free,but I found it too simple to design cavity filter,have you used Ansoft Designer 1.2 or any higher edition,I think it could be better.

Hello Madhuen and the others.
I think all those expensive softwares cannot help you very much. They are basicaly just simulators, that means they just do analysis. They don't do synthesis.

I think you have 2 ways to go:

1- With an expensive and professional software you can start with a rough structure based in Dishal's papers. Then run an optimizer and wait forever to get the right dimensions. This will be a kind of general method. Maybe D.Swanson's book could help you somehow in how to aproach the filter synthesis problem using an optimizer....

2-The second option, that is the one I propose you is to use simple programs that were developed by great people (mainlly radio amateurs) in the past that again, based in Dishal's and others papers make the sythesis ( the design) for you. After you have the design you can even run a simulation tool for verification and run an optimizer to improve it if it is needed (I think it will not be needed, anyway).

To help you in the method 2 just follow the great web page from Mr. Turner:
http://www.ussc.com/~uarc/utah_atv/interdigital1.html
There you will find everything needed to make your design.
The BASIC program was developped by Dale Heatherington, WA4DSY. This program can also be found online in the following address:
http://www.wa4dsy.net/cgi-bin/idbpf

I would also invite you to take a look in the following important papers:
1-M Dishal ?A Simple Design Procedure for Small Percentage Bandwidth Round Rod Interdigital Filters? MTT -13 Sept 1965 p 696
2-E.G. Cristal ?Capacity Coupling Shortens Combline Filters? Microwaves, Dec 1967, p 44

I think that is all you need.
S.

hfss+designer
you can insert hfss into designer

A very good tool for cavity filter design is MWWizard from Mician.

www.mici@n.com


bye

CST is the better software to simulate the cavity filter,but for filter synthesis, you should write synthesis program by yourself,you can refer to Cameron's paper in MTT.

hi
those article you all refer to i can search from google,how can i find them .?
thanks

Hi all, in my last post I gave the wrong link to MMWizard the right one is

H**t://www.mician.com

It is a very fine tool implementing the mode matching method, and it includes also a sinthesys tool.


Hope this can help

Hello Sinatra,

It would be great if you could upload those 2 papers here.

A couple people -might- have the Dishal one on an old MTT CD; but it'd be nice to have it here; and also, the Cristal one will be very hard to find for most folks without an engineering-library next-door... :D

thanks!

designer is better

i use hfss to sp 3d model and get a group of S sp then insert this group to designer and design the wg filter.

i use hfss too,it is very good

i just use hfss simulating the cavity,it is good

Added after 9 minutes:

i do need the two papers ,but i have not points,

If you simulate combline filter with HFSS, next article is very helpful.

h**p://www.ansoft.com/hfworkshop04/2004_HFSS_Users_Workshop_Douglas_Dawson.pdf

This tutorial might help

ansoft Designer +cst,or ansoft Designer+hfss.

Hi Everyone

This may help too