Distributed Element Filter Footprint

[viniciuslbar]

I am really a newbie in Kicad.
My goal is to designed the PCB layout of a receiver. The point is that I have a bandpass filter in the channel which I designed as a distributed element filter. I have all the dimensions of its structure (simulated in a EM software) and at first I thought that would be possible to create a footprint of its structure. Then, whenever I need to use this filter I could call this component and then I would have my filter in the layout. But then I realized maybe this is not so simple because the only parts possible to set to top layer/bottom layer in the footprint editor are the pads. Thus, I can’t draw the copper parts of the filter structure. In addition, the structure would have some fill zones and plated vias that I also not sure if it is possible to do in footprint editor.

Anyone has a idea how to do it or have already done something like this?
Thanks in advance.

[maui]

hi, you can get some tips here

Antenna for a Nordic Semiconductor nRF8001 Bluetooth Module

I found a reference design here (see the image below). I’m guessing the antenna is that trace around C5 and C6. This is the same design in the datasheet. I also found a document on antenna tuning with lots of equations and the need for some expensive equipment. [image] Adafruit also has a design with a completely different antenna. I may just copy the Nordic’s design, spin a PCB, and give it a try. But I’m not really sure how I would tests it’s efficiency.

KiCad 3.0 - Making A PCB Antenna in KiCad

Gerber to Footprint

Made the video this morning, hopefully it helps clear things up: [KiCad 3.0 - Making A PCB Antenna in KiCad]

Filled area from imported DXF

one option is to import your dxf shape in pcb footprint editor and export it as a module .kicad_mod then open it in text editor and collect the point modifying it from fp_line / fp_arc in polygon to see how a polygon is done in kicad just create a new board and place a fill zone, save the board and open it in text editor then convert your point to the fill zone structure and assign it’s net to the net node you need if everything went fine if you re-open your board you will have a fill zone w…

[viniciuslbar]

You gave me a nice start point.
For some reason, .dxf didn’t work properly. I guess I will try to draw the copper structure, just like in @ChrisGammell’s tutorial. Anyway, my structure is not as simple as a microstrip antenna. I need to add platted vias and fill zone areas (these are need to build CPW structure).

[maui]

Have a look here

Creating an elliptical PCB? [solved]

Hi, as Marco Hess pointed out in kicad developers mailing list, if DXF R12 is used e.g. through LibreCAD, ellipse are converted to line segments and then kicad will load it correctly. if the ellipse will be not completely closed it is easy to add a small segment to the pcb edge and the board will render fine also in 3d-viewer… thanks Marco! PS Marco has patched also the “missing closing ellipse” Regards Maurice

dxf must be ascii, R12 and without polylines

to have a filled area i think the only workaround is to create a fill zone from your dxf points getting from the imported footprint…
it would be nice to have a python script for the conversion…

[viniciuslbar]

I followed the video tutorial but then when I added the .mod footprint the structure didn’t look as expected.

The bottom part should be a perfect rectangle. However, it got some imperfection that I can’t allow since it is a RF part. What could be the problem here?

teste.kicad_mod (1.3 KB)

[maui]

this seems fine (Kicad stable under windows)

teste-neg.kicad_mod (1.3 KB)
I used bitmap2component 300dpi, threshold 50%, negative

[viniciuslbar]

Really strange. Did you use my .svg file?
I used just the same parameters as you in bitmap2component.

[maui]

I used the png that you attached …

[thewyliestcoyote]

This is something that I have wanted from Kicad for a long time. I have put off doing much descubated element stuff in Kicad (I have a legal ADS license), but the little I have done has been with the footprint editor and just placing pads of the right size of shape and naming them correctly. I is hard to do much stuff with distributed elements without some kind of build in simulation tools, be it transmission line approximation or 2D or 3D simulators. I have been toying with how to add in anyway support for distributed element stuff in kicad. It makes me very happy to know that I am not the only person that thinks they could make use of these features.

A “quick” way to do it programmatically now that the python scripting supports footprint wizards would be to make a distributed element import wizard. In fact I think I am inspired to give that a try some time over the next couple of weeks.

Btw: What EM software are you using?
maybe it can export a more friendly file type svg’s.

Best,
Wylie

[viniciuslbar]

I agree it’s good to know that you’re not alone facing such problem, @thewyliestcoyote!
It would be great to have those features.
I’ve already read about the possibility of using python to develop scripts but I don’t think I have enough knowledge on python to write such script (actually, I don’t have enough time now to spend on it).

I designed and simulated the filter in HFSS.
I’ve tried to export .dxf from it but it didn’t work.

[thewyliestcoyote]

Haha,
I have not had a day using HFSS that I have not found some problem with it or getting it to work with other tools. Funny for a tool that the company was paying so much money for.

Yeah kicad DXF handling sucks kind of hard for anything other than the most simple of things. This has no rounded edges or anything like that so I am not sure why you couldn’t just do it that way.

Myself and a couple of my colleagues have written some 2D and 3D simulation tools (FDTD, FEM, and MoM) that we will maybe making public hopefully this next year. Its my personal goal to make them usable form kicad. I want to not have to use ADS or HFSS for things other than IC’s and MMIC’s.

I will post the small collection of tools when I have something worth sharing, I will PM you when I have kind of a Alpha version so you can give it a try. I am kind of backed up for the next couple of weeks so no promesses when that will be.

[viniciuslbar]

Yes, I hoped the process of export dxf file would be simple. As you said, the structure I dealing with is far from complicated. Anyway, best luck next time.
The bitmap2component workaround seems not so reliable for me, although it is all I have at the moment.

That’s great! But keep secret about it. Otherwise, ADS and Ansys fellows will come after you! haha
I am looking forward to giving a try when you have it.

[tipofthesword]

I’m really looking forward to this! Please sign me up for beta testing.
Currently I’ve been using openems.de which is purely script based which makes it more difficult to use

[thewyliestcoyote]

If I ever get some free time to work on it,

I was planning on having it being a Footprint wizard. This way the user does not have to deal with anything having to do with running the script. I have made a couple of other tools like this for making test fixtures and odd components and it have proven to very good tool.

I will post here when I get something working and ready for testing.