Sonsivri

Hi all

When you draw a ground zone, there is no problem if you draw ONE zone.
If you draw more than one, there will be a "clearance" between zones, even if you have , of course, same ground relation (power...)
Here I can set a global zone but, near component antenna zone only, I need to expand clearance so , to do that, I'm searching a solution.

Is there one ?

Thanks.

I see two options:
1. Integrate antenna zone to existing one by adding new points to it. Disadvantages: antenna zone will have the same parameters as "another" zone.
2. Just connect two zones by route of needed size.

1) I don't understand exactly what you mean!. Don't see the difference with (2)
2) I know (and use) this  but it's not very nice solution

See following picture


(http://img15.hostingpics.net/pics/641230PCBzone.jpg)

I mean that you can make one more complex zone (1) or connect two zones by route (2). And there is a difference.

The picture you showed has weak connection to previous questions, I think.

For the pin that needs more clearance:
 a) edit properties of pin before composing it to package and change "zone clearance" property.
or
 b) place similar pin with changed "zone clearance" on top of packaged pin
or
 c) surround this pin by another zone with the same net and change clearance for it.

For the pin that needs to be be unconnected from zone change "Relief" to NONE in "Edit pin" dialog.

There is another way: "Defining a Keepout Area inside a Power Plane": inside an existing plane make another zone and set its type to "Empty" at creation.

Posted on: October 21, 2015, 10:41:59 22:41 - Automerged

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The strange angled line (feeder) form RF module to antenna looks not perfect for me. Or is it the correct/normal way? Are there any recommendations/limitations in module's datasheet? What frequency? Just curious.

If you have the digital and analog  ground zone in the same pcb,  for example, I use different nets and connect through the 0R resistor.

If you want to give more space between a pad and a ground I use keep out zone.

To "Signal":

OK, it's a good solution you give to me. Thanks.

The strange angle is because I need two things:
- antenna must be nearest from board side because I don't use screws for box, it's antenna witch maintain  box closed.
- angle is due to ESD component and small board size. Do you think it will be better to move up antenna ?



To "EDsonct"
Yes, I did it sometime but I din't think it will be different from making manually ground zone and, after, connect spaces with wires.

I'd move antenna to get more space for line and SMD. But I do not have experience in RF, just theoretical knowledge. So I can not predict if your layout is just imperfect but fully working and loose only couple of % of performance or is significantly bad.

On RF a strip line is not just a connector. It's dimensions depend on required impedance, material an thickness of the board. Gap between line and ground plane has the same importance. Each non-uniformity as a change of width or direction has meanings because of reflections - that can be modeled as inductance for example and can acts as a filter or radiating antenna. When protection elements are placed it is common to make it as imperceptible as possible - pads are placed on line and ground without changing their geometry.

So a line from RF module to SMA connector is not just a PCB trace. It is a system of correct trace, correct gap (clearance), and ground plane with required minimum size around and/or underlying ground plane (and vias). To change trace/line direction a radius (with recommended minimum) is used.

Thinking this manner the thermal relief connection of ground antenna connector pins is also not appropriate here.

In short, if you want to make it correctly you do not need to research and come up with an invention. You just need to find appropriate guidance for PCB layout with exact dimensions for your case. Datasheet of your RF module or accompanying documents from manufacturers of module and SMA connector is a good place to start from.

For example: (image from https://www.altera.com/support/support-resources/support-centers/board-design-guidelines.html)
(https://www.altera.com/content/dam/altera-www/global/en_US/images/technology/signal/images/fig5-sma-tear-dropping.jpg)

Hi

I removed IC to be sure.
Here is the original PCB (frequency 868Mhz)


(http://img15.hostingpics.net/pics/964208Originalantennapart.jpg)

Looks rather oriental than original.
Never like copying without understanding. It's better to see this layout on "paper" from "IC" manufacturer than expect a secret knowledge of Chinese PCB designer.

I have only two concerns:
1) thermal relief connections to ground pins of module and SMA that are not complementary with signal output connection.
2) too sharp change of width from out pin to line.
Wide trace is due to two layer board with ground plane underneath far from top layer I think (better to say "guess"). Round window in ground is required for on-module antenna connector?

Will wait for experts - what would they say?

Ok, I did this. I hope it will be correct (but it will be much more than before  ::)

(empty zone is for cutting PCB because IC is too difficult to be soldered manually. Antenna "guard gap" has been minimised too but not on those screen capture)

(http://img15.hostingpics.net/pics/885328PCBzone.jpg)

(http://img15.hostingpics.net/pics/8121043DPCBzone.jpg)