Layout Design in KiCad, How to create the circular ring in Kicad?

[Swadesh]

Can somebody please suggest how to design the pcb layout using KiCad. I am new in KiCad. Thanks in advance.

[jos]

Use the circle, or draw arc commands on right hand side. If you need straight ends then you can make them with a small fill zone. Zones can be drawn and shaped in just about any way desired.

Another way is to approximate the circular segments completely made up of fill zones.

[jos]

This spiral inductor program should do the trick even better.

[Swadesh]

Thanks for your reply. will follow that. As I am new in KiCad, Just for my understanding, do I need to work on “schematic layout editor” and “symbol editor” or I can directly start designing from “PCB layout editor”

[jos]

In general a design begins with a schematic.

From there you press F8 to transfer the information about components and nets to Pcbnew within which you then start to arrange components as desired and model the layout as needed.

You will need to go back and forth between schematic and layout to fine tune your design.
Can be tricky though lots of fun.

[Swadesh]

Hi before doing anything difficult, I would like to start something simple like this fig. circuit is for unit cell (1 ring with active/passive components). Can you please guide me how can I do that?

[jos]

In this case it should be possible to make a reusable footprint.

Open the foot print editor.

• Click on create new foot print Cltr+N (top left symbol)
• Place pads and make them smd pads likely without paste mask
• Make the outer ring (shape/s) with the draw line/circle/arc commands on the rhs of screen
• Size and place pins. Can’t tell from the picture if the ring has a gap

You can merge a pin with any shape/s by selecting the pin, one or more shapes.
Then right click ‘Create pad from selected shape’, and so on.

You need to play with it.

What’s the FET’s casing? TO-something?

Cheers

[Swadesh]

This is the equivalent FET model( [CE3512K2] from Digikey I found. This is the detailed picture. Can you please suggest if my operating frequency is around 7 GHz, what are the consideration for inductior and capacitor mentioned in the picture?

[jos]

Looks like you are in for some decent reading for a start.

What you are dealing with is serious stuff needing highest precision, lots of calulations, and subsequent tests. Not to mention the necessary test equipment.

Those might help as well.

• Luceda Photonics
• Optiwave
• Hetero Junction FET

and many more searchable resources in the net.

Edit

Quite interesting isn’t it

[Swadesh]

Yes, I am working on that paper. Precision and state of the art measurement setup is required in order to find out Faraday rotation and anisotropic behaviour. Trying to mimic the same task of them and in parallel trying to design different structure in HF in Ansys simulation software (If you have any suggestion on that, that would be excellent).

[Swadesh]

" * Click on create new foot print Cltr+N (top left symbol)

• Place pads and make them smd pads likely without paste mask
• Make the outer ring (shape/s) with the draw line/circle/arc commands on the rhs of screen
• Size and place pins. Can’t tell from the picture if the ring has a gap"

Hi Jos,
Can you please describe your point 3 and 4 a lil bit. I am little bit struggle with this. ring has gaps.

[jos]

Footprint editor

Make shape(s) with the drawing tools on the right hand side.

• Line, circle, arc, graphic polygon. It does not matter. Use whatever constitutes the shape you need.
• Place a pad (circular or rectangle) inside it. (Used as anchor for the combined pad -> defines the place where you can later connect traces to the pad.)
• Select the lot with the mouse
• Right click, select ‘Create pad from selected shapes’
• Now you have a custom shaped pad.

Pretty much any shape is possible. You need to play around with it to get the hang of it.

Cheers