how a RF connector being connected onto complex RF PCB

ZCochran98

Joined Jul 24, 2018
304
We use these at work. Summary: the launch pin sits on the trace (tapered up or down to the pin width), while you need to have a sizeable ground pad on either side of the trace that contain GND vias to layer 2, while also having mounting holes that go top to bottom. Backside of the board should have a GND plane that connects up to the RF GND by some vias as well where the connector sits. It'd end up looking (roughly) like this on top:
1705024865736.png
And this on bottom:
1705024886459.png
That inner rectangle is the RF GND (bigger than the connector), while the metal separated from it is the DC GND (if you are keeping DC and RF GNDs separated - otherwise, you don't need the gap). Layer 2 then is just a full plane over the entire board for RF GND.
The taper isn't necessary, but it can help with the transition from coax to microstrip.
Don't forget to keep this area free of soldermask.
 

Thread Starter

yef smith

Joined Aug 2, 2020
755
Hello , from the photo below i see that i need Guard VIA surrounding the trace and 2 mounting holes.
both VIA and mounting holes are going thew the whole PCB.
how does the connector know to connect to the inner middle RF GND layer?
Thanks.

1705045672747.png
 

ZCochran98

Joined Jul 24, 2018
304
The backside RF GND plane is connected to the topside RF GND plane and the layer 2 RF GND plane by the vias. The connector is a clamp-on, so the top half of the "clamp" makes contact with the top RF GND, the bottom half of the "clamp" makes contact with the bottom RF GND, and the vias assert that there is an electrical connection from both to the layer 2 RF GND.
 

Thread Starter

yef smith

Joined Aug 2, 2020
755
Hello, i am having trouble to imaginge your words.
Could you please draw roughly how the conector clamps on the PCB shown below?
Thanks.
1705164889736.png
 

ZCochran98

Joined Jul 24, 2018
304
1705175747618.png
Crudely drawn, it looks a bit like this. The next picture kind of illustrates what it looks like on a board:
1705175800898.jpeg
The next pictures show a side view of a similar connector (not Southwest Microwave-branded, but connects nearly identically):
1705175871403.jpeg1705175922771.jpeg
Hope this clears things up!
 

nsaspook

Joined Aug 27, 2009
13,279
Hello, i am having trouble to imaginge your words.
Could you please draw roughly how the conector clamps on the PCB shown below?
Thanks.
View attachment 312629
Looks like a stripline to me. That seems to be a problem with your selected edge clamp connector. :rolleyes:


https://store-68dp4b.mybigcommerce.com/content/Technical_Articles/SMI-End-Launch-Connectors.pdf

https://resources.altium.com/p/stri...-differences-and-their-pcb-routing-guidelines

1705182483574.png

https://resources.altium.com/p/stri...-differences-and-their-pcb-routing-guidelines
 

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