Is there anyone designing microstrip line filter?

Do you have any idea of how to make transmission zero? I reallize the best way is using CQ filter to make TZ, but in papers, most authors list the useless equations to realize correct filter pattern. Is there anyone have experiences in it? Please share me that. Thanks

ps. Have you ever hear about the superconductor filter or some information about that?

what is CQ filter?

This site http://web.bham.ac.uk/K.S.K.Yeo/Publications.htm lists items that you requested information about. CQ stands for cascaded quadruplet. This seems to be a two dimensional array of nodes connected by transmission lines. Look at the illustration in http://www.sonnetusa.com/products/em/new_features.asp This reminds me of Brillouin Zones.

There are three basic ways of making zeros.

1. Shunt transmission line that shorts out a signal path at one frequency.

2. Coupled network that sucks out energy at one frequency.

3. Phasing two paths together so that they are out of phase (and subtract) at one frequency.

The Filpro software available at http://educ.rfglobalnet.com/software...tegories/9.htm designs these filters. It is very obtuse and user unfriendly to operate.

zero means transfer nothing.so reflect signal or absorb signal are all functional.