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Layout software has long been integrated into the microwave vendor design suites. The problem with this integration is twofold: usually the interface is frustrating, and often, a mechanical engineer is responsible for final layout of a design, and he sure as heck isn't gonna go for using a microwave analysis tool when there are lots better ME packages available that he might want to learn to build his (or her resume).
The layout software that you use depends on what product you are developing. Let's divide layout software into three categories:
Laying out thin-film networks
Laying out printed wiring boards
Free PWB software!
Laying out MMICs
The one thing that is wrong (in our opinion) in the printed-circuit industry today is the use of the Gerber interface. Dating back to the 1970s, this arcane language asks you to define apertures and flashes, just as if you were drawing the artwork with a miniature flashlight (in the old days you were indeed doing that!) Today's modern photo-plotter uses a laser raster scan, but quite often the laser must be driven from a .gbr file. Not many software packages can read Gerber files. Want a free Gerber previewer? Graphicode has one for you!
Laying out thin-film networks
One of our favorite layout software tools is AutoCAD. The same software that you might use to plant bushes on your next house plot plan. AutoCAD does it all, it isn't hard to learn, and it fits onto your PC with room to spare. The output of a file can be put into different formats such as .dxf, which are "readable" in many other CAD programs.
Laying out printed wiring boards
If you want to generate a multilayer layout from a schematic, AutoCAD is too limited. Try Protel. Or try some freeware... see below!
Free printed circuit board software
Here's some links to suppliers that will etch prototype boards cheaply. They get free links on this page, just because we like this kind of service! But please tell them we recommended them.
Cheap FR-4 printed wiring boards might not be the best way to manufacture a microwave circuit card, these ultra-cheap board fab houses can be useful, especially with free online design rule checking (DRC) that checks your gerber files for manufacturability issues, and other freeware. FR-4 boards are great for all the ancillary stuff that goes with microwave engineering, such as regulators and control circuits.
Express PCB is home of the $51 circuit board, and they'll give you free software for doing the layout.
Advanced Circuits is home to the $33 each and $66 each boards. They also make barebones boards without soldermask for cheap, and have overnight and weekend turnaround options as well as deals for starving engineering students. The best part is that they also have their own free layout software, as well as free online design rule check. Thanks to Sarah!
PCBExpress (owned by Sunstone Circuits (offers a similar service, with two boards etched for $60. Check them out at Sunstone.com! Their site offers a ton of freeware, and a PCB tutorial. Thanks to Dawn for providing the updated link in May 2012. Tell them that Microwaves101 sent you!
Or you can try the PCB Creator software from Bay Area Circuits. According to their outreach rep Nicole, this PCB layout and schematic capture software lets you create 2 to 4 layer custom PCBs. And it's free, so the price is right!
New for December 2018: Here are some more utilities, recommended to us by loyal v iewerTitus:
We generate DXFs directly from our EM software, but there are some post-processing steps we need a free DXF editor for; which is where DoubleCAD XT Lite comes in. We use it to panelise, draw routing layers, add over-etch / under-etch and drill hole compensation (there's a pretty nifty offset tool for that), an just generally create PCB layers... stuff like that. Works like a charm.
After we've created our full DXF panel and converted it to Gerber, we found it handy to import the Gerbers using Pentalogix ViewMate Gerber Viewer, a tool similar to the ones the CAM operators use, just to be sure that they see what we see. It also imports and views NC drill files.
Laying out MMICs
Some of the more expensive EDA tools can at least get your layout started. Chances are you will have to finish the design in Cadence.