I really like FilterFree from NuHertz
http://www.filter-solutions.com/
Great software, and quite reasonably priced for the "pro" versions. Like
Anasoft, NuHertz is largely a one-man band -- Jeff Kahler, although this seems
to be changing now that AWR is integrating Filter Solutions into Microwave
Office. The one thing I'd like to see in his software is various filter
transforms... I'm sure Jeff is quite familiar with, e.g., Norton transforms,
and it's surprising that he doesn't have them when other software (such as
AADE Filter Designer) does. (Since AWR has integrated Filter Solutions, I
imagine they might bankroll the addition of such transforms, as some of AWR's
direct competition -- Eagleware Genesys, aka Randy Rhea's retirement plan, now
owned by Agilent -- has a very comphrensive set of transforms built-in.)
NuHertz is also a little like Anasoft in that the GUI's "kinda different" -- I
often have the impression that Jeff must still be working with a 640x480
monitor or something.
---Joel