What software do you use to make PCBs with microstrip components?

[bjcuizon]

I'm not really sure where to post this thing (I thought I'd put it in the beginners section or in RF,Microwave Section) but anyway, as the title of the topic says, I wanted to ask what you guys use to layout microstrip line components and such. I'm still a hobbyist and I do not have money to spend on professional software like Altium or others...So what would you recommend? Can you use the FreeVersion Eagle/KiCad? Thanks.

[Alex Eisenhut]

Well, we do the simulations in Ansys, structures are exported in DXF, imported into Allegro.

Here you can either create a schematic symbol of the component (like a hybrid coupler, or filter) is created, so that the corresponding RF structure becomes a footprint with well defined connection points. Properties are added in the schematic (net_short) on the pins because unless you have the RF feature ($$$) Allegro has a hard time figuring out that a big blob of copper is a RF part, and not a short-circuit.

The advantage of that is that the RF structure can be easily manipulated like any other footprint.

You do need to keep track of units because DXF is terrible, if you import a metric structure as imperial, you're in trouble.

Allegro's RF feature I'm not familiar with. Apparently it lets you create all kinds of structures directly in the layout with parameters from Ansys.

Never tried it. My DXF/footprint approach works well enough for now. I've done many layouts like this with 5 to 6 structures per design.

Now for your other question, you can use whatever you want because the PCB software should be able to import a set of X,Y coordinates to draw the shape as a copper shape. It might not understand the purpose of the structure, and generate lots of errors, you just have to be careful.

Just pay attention to units and scale. Otherwise that Ka-band hybrid coupler you designed might only work at L band...

In many ways, you don't need much in terms of PCB software, except as a tool to create gerber files.

[bjcuizon]

Thanks very much! I did not know Altium had free CircuitMaker. I'm pretty new in terms of PCB design and/or software.

[nctnico]

Differential pairs / microstrip / stripline structures are all about width and clearance so you can use anything to create these kind of circuits. There are tons of online tools for calculating trace impedances.

Using a package which can automate (part) of creating these can help but it is only cost effective if it saves you a lot of time. And there will also be a learning curve to set things up correctly so their is an effort/reward ratio to think about.

[David Hess]

I do the layout in AutoCAD like would have been done using transparencies and tape in the past.

[bjcuizon]

I do the layout in AutoCAD like would have been done using transparencies and tape in the past.

But isn't AutoCAD a software you need to pay for? (Well, unless if you have the crack version which is...kind of illegal.)

Anyhow, I already downloaded CircuitMaker from Altium. Its pretty neat though...and I'm still learning how to use it.
Thanks.

[Alex Eisenhut]

Get Draftsight, it's a AutoCAD-like tool.

https://www.3ds.com/products-services/draftsight-cad-software/free-download/

[bjcuizon]

Thanks. I'll try to download that later. Is there a way of getting gerber files out of autocad or draftsight?

[David Hess]

Get Draftsight, it's a AutoCAD-like tool.

https://www.3ds.com/products-services/draftsight-cad-software/free-download/

I will check DraftSight out since I like the AutoCAD interface.  Thanks for mentioning it.

The similar interface allows AutoCAD users to feel right at home, where as those who start with DraftSight don’t feel any problems when migrating to any other 3D/AutoCAD look-alike CAD software.

[Alex Eisenhut]

Thanks. I'll try to download that later. Is there a way of getting gerber files out of autocad or draftsight?

Not really, I suppose you could make an interface but that will be a world of pain, IMO. I wonder if there's a Gerber print driver? 

Some PCB vendors will take DXF data directly. We do it when a board is just a line-up: input, device, output. We just add the stubs and biasing and that's it. Two layers, maybe 30-40 drill hits.

[Smokey]

This seems due for an update.  What are the software options for controlled impedance RF PCB design in 2022?

[mc172]

What does "controlled impedance design" even mean?

[Smokey]

Microstrips, Coplanar waveguide, etc.
Are there better, more available, tools for creating and evaluating this sort of RF design element in 2022.

[mc172]

It was somewhat rhetorical. I see the term bandied about a lot, especially from PCB manufacturers and it winds me up a bit. Apologies, this isn't adding anything of value, it's a pet peeve. There's a thread for that! I'll get my coat.

[Smokey]

All good.  I'm not an RF guy, so I know I'm not speaking the right dialect of EE. 

[mc172]

To answer your question - I don't know of any RF-specific layout tools. Such a thing would be nice in principle but in reality I think it'd be a hindrance. When doing RF layout work  the transmission lines are at the bottom of the pile as their performance is predictable before even thinking about them. In my experience the bulk of the work is tweaking clearances around specific components in order to manipulate the parasitics.

Transmission lines are done easily with clearance rules and zones - you know how much power you're dealing with which dictates the minimum trace width and you know the impedance you want, therefore you are most of the way towards calculating the parameters of your transmission line. Decide your board thickness and the dielectric material and you're there.
Automating this with a CAD package I think would cause more problems than it solves.

[simon mugo]

you can use any software that you can afford and are comfortable using it. Thanks.