See "90-degree Corners: The Final Turn" in the January 1998 issue of
Printed Circuit Design magazine.
Doug Brooks, mentioned below, authored this piece and participated in
the "Test Lab" for PCD by creating a test board with a variety of
traces--including 90-degree, 45-degree mitered and sharp 135-degree.
Each trace was examined using a TDR at the University of
Missouri-Rolla Electromagnetic Compatibility Laboratory. You may order
copies of the issue for $7 by calling 888-847-6177 or 847-647-8602.
Ronda Faries
Senior Editor
Printed Circuit Design
www.pcdmag.com
770-952-1303
______________________________ Forward Header __________________________________
Subject: Re: [SI-LIST] : Design Note on Right Angle Bends
Author: Nirmal Jain <[email protected]> at Internet
Date: 7/10/98 3:36 PM
Dear Mike,
The electrical structure would behave like an antenna when it's length
becomes comparable to the wavelenght of the signal it is carrying. The
length of 90 degree bend is higher than 45 degree bend, so 90 degree
bend acts like an antenna at lower frequencies than 45 degree bend.
I would start worrying about these bends at the edge rates of 100ps and
below.
Hope it helps. Regards
Nirmal
Mike Mayer wrote:
>
> I am puzzled by a design note on the Ultracad web site:
>
> http://www.ultracad.com/tech.htm
>
> It states that:
>
> THE REASON YOU DON'T USE RIGHT ANGLE TURNS ON CIRCUIT BOARDS IS
> THAT RIGHT ANGLE CORNERS BEGIN TO LOOK LIKE ANTENNAS.
>
> There are no references given or any further explanation. Can anyone
> explain what they mean?
>
> --
> =============================================================================
> Mike Mayer Artesyn Communication Products, Inc
> Madison, WI
> http://www.artesyn.com/cp
> =============================================================================
>
> **** To unsubscribe from si-list: send e-mail to [email protected].
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-- Nirmal Jain Ansoft Corporation (412)261-3200 X129 (W) Four Station Sq., Suite 660 (412)261-471-9427(FAX) Pittsburgh, PA 15219 _________________________________________________________________________ Check out Ansoft's WWW site at http://www.ansoft.com for product information, technical support, employment opportunities, much more... ------------------------------------------------------------------------- **** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list **** --IMA.Boundary.1318010090 Content-Type: text/plain; charset=US-ASCII; name="RFC822 message headers" Content-Transfer-Encoding: 7bit Content-Description: cc:Mail note part Content-Disposition: inline; filename="RFC822 message headers"Received: from betty.mfi.com ([198.71.19.36]) by sf-mail.mfi.com with SMTP (IMA Internet Exchange 3.01 Enterprise) id 0011C3F8; Fri, 10 Jul 98 13:56:09 -0700 Received: from alto.mfi.com (alto.mfi.com [198.71.19.38]) by betty.mfi.com (8.8.8/8.8.8) with SMTP id NAA25560 for <[email protected]>; Fri, 10 Jul 1998 13:03:51 -0700 (PDT) Received: from mercury.Sun.COM ([192.9.25.1]) by alto.mfi.com via smtpd (for betty.mfi.com [198.71.19.36]) with SMTP; 10 Jul 1998 19:59:33 UT Received: from Eng.Sun.COM (engmail4 [129.144.134.6]) by mercury.Sun.COM (SMI-8.6/mail.byaddr) with SMTP id MAA15887; Fri, 10 Jul 1998 12:56:02 -0700 Received: from silab.eng.sun.com (silab.Eng.Sun.COM [129.146.121.121]) by Eng.Sun.COM (SMI-8.6/SMI-5.3) with SMTP id MAA02697; Fri, 10 Jul 1998 12:55:59 -0700 Received: by silab.eng.sun.com (SMI-8.6/SMI-SVR4) id MAA08039; Fri, 10 Jul 1998 12:44:35 -0700 Errors-To: [email protected] Received: from Eng.Sun.COM by silab.eng.sun.com (SMI-8.6/SMI-SVR4) id MAA08035; Fri, 10 Jul 1998 12:44:31 -0700 Received: from earth.sun.com (earth.EBay.Sun.COM [129.150.69.3]) by Eng.Sun.COM (SMI-8.6/SMI-5.3) with SMTP id MAA12358 for <[email protected]>; Fri, 10 Jul 1998 12:42:51 -0700 Received: from maxwell.ansoft.com (maxwell.ansoft.com [192.149.1.1]) by earth.sun.com (8.8.8/8.8.8) with SMTP id MAA06246 for <[email protected]>; Fri, 10 Jul 1998 12:42:52 -0700 (PDT) Received: from eel.ansoft.com ([192.149.1.155]) by maxwell.ansoft.com (4.1/SMI-4.1) id AA03781; Fri, 10 Jul 98 15:38:26 EDT Received: from eel by eel.ansoft.com (SMI-8.6/SMI-SVR4) id PAA23947; Fri, 10 Jul 1998 15:36:38 -0400 Message-Id: <[email protected]> Date: Fri, 10 Jul 1998 15:36:37 -0400 From: Nirmal Jain <[email protected]> X-Mailer: Mozilla 3.01Gold (X11; I; SunOS 5.5.1 sun4u) Mime-Version: 1.0 To: Mike Mayer <[email protected]> Cc: [email protected] Subject: Re: [SI-LIST] : Design Note on Right Angle Bends References: <[email protected]> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: [email protected] Precedence: bulk --IMA.Boundary.1318010090--