In addition to all the references cited so far there was a paper published
in the 1998 IEEE International Microwave Symposium Digest by Ponchak et al.
"Characterization of Plated Via Hole Fences of Isolation Between Stripline
Circuits in LTCC Packages" IEEE reprint # 0-7803-4471-5/98.
To summarize the results:
The frequency range examined was 10-40 GHz
Via-via spacing of 1.3x to 5x the via diameter
Via fences should be 4x the strip to ground plane distance
Using fences only locally where isolation is required actually degrades the
characteristics due to field perturbations that extend past end of the
Additional references cited in the article are:
"EM Modeling of Via Wall Structures for High Isolation Stripline" J. W.
Grippich, IEEE Int't Microwave Symposium Digest, 1994
"Multi-layered 3-D Packaging Issues" J. W. Grippich et al., IEEE Int't
Microwave Symposium Digest, 1997
Colorado Springs, CO
> -----Original Message-----
> From: Elya B. Joffe [SMTP:email@example.com]
> Sent: Thursday, September 02, 1999 11:44 AM
> To: Elya B. Joffe; firstname.lastname@example.org; Vinu Arumugham;
> email@example.com; John Lin - TAO; Howard Johnson; Gert Winkler; Ron
> Matthews; Roland F. Portman
> Subject: [SI-LIST] : "Picket Fence" (Via Fence) for increasing
> isolation between
> Dear Members,
> I am involved in a project where we must apply the technique of
> "Picket Fence" (Via Fence) for increasing isolation between
> conductors on a PCB.
> I cannot find any refercnes (papers, books, etc.) on that issue. Are
> you familiar with anything on that issue? The problem, basically, is
> - how much isolation can we get between conductors embedded between
> ground planes, or between ground and power planes, when they are
> "isolated" by a "picket/via fence".
> If you have come across such material, or references, I would be
> grateful if you could refer me to them. I have gone through the
> "classics" and could find nothing there, and I need some references
> for the work we are involved in...
> Elya B. Joffe - EMC Engineer
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