Ground plane settings for RF?

Hi guys, I'm trying to desing PCB for RF applications and I'm getting confused about ground plane....

My track is 0,75mm width and I need 0,15mm space from surrounding ground plane (to achieve specific track impedence).

I design ground plane but even setting Isolate to 0 value I still have more than 0,15mm spacing from ground; so I need to set Clearance value to 0,15mm into design rules, but in this way all tracks of board get spaced of 0,15mm.

How can I set specific spacing ONLY for specifico polygon?

Thanks.

0 clem57 over 9 years ago

HOW-TO: Polygons and ground fills for PCBs in Eagle | Dangerous Prototypes
or https://www.sparkfun.com/tutorials/115
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0 Former Member over 9 years ago in reply to clem57

Thanks, but I've already read similar tutorials.....
I've tryed to solve in this way:
1) set Clearance value to 0 mil (wire field) into net Design rules
2) set Isolate to 0.15mm into first ground plane (antenna ground plane)
2) set a second ground plane for remaining PCB with standard Clearance value

I don't know if this way is the correct one.....
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0 autodeskguest over 9 years ago in reply to Former Member

On 06/17/2015 01:42 PM, Michele Bertoni wrote:
Thanks, but I've already read similar tutorials.....
I've tryed to solve in this way:
1) set Clearance value to 0 mil (wire field) into net Design rules
2) set Isolate to 0.15mm into first ground plane (antenna ground plane)
2) set a second ground plane for remaining PCB with standard Clearance
value

I don't know if this way is the correct one.....

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Did you use the net class functions. I don't know where you access it in
the newer versions.
Paul
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0 dukepro over 9 years ago

Can you add a second ground polygon immediately surrounding the 0.75mm
track? This would allow you to set the spacing for the portion of the
ground plane surrounding the track different than that of the overall
ground plane. The DRC settings would have to be the lesser of the two,
of course.

On 06/17/2015 10:49 AM, Michele Bertoni wrote:
Hi guys, I'm trying to desing PCB for RF applications and I'm getting
confused about ground plane....
My track is 0,75mm width and I need 0,15mm space from surrounding ground
plane (to achieve specific track impedence).
I design ground plane but even setting Isolate to 0 value I still have
more than 0,15mm spacing from ground; so I need to set Clearance value
to 0,15mm into design rules, but in this way all tracks of board get
spaced of 0,15mm.
How can I set specific spacing ONLY for specifico polygon?
Thanks.

--
To view any images and attachments in this post, visit:
http://www.element14.com/community/message/152867
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