[SI-LIST] : Microstrip losses

WAUGH,RAY (ray_waugh@am.exch.hp.com)
Thu, 22 Jul 1999 09:13:56 -0600

Chris...

Indeed, the dielectric losses dominate in embedded microstrip and in
stripline, just as they do in conventional microstrip.

Ray

-----Original Message-----
From: Chris_Heard@ne.3com.com [mailto:Chris_Heard@ne.3com.com]
Sent: Monday, July 19, 1999 5:23 PM
To: si-list@silab.eng.sun.com
Subject: RE: [SI-LIST] : even-odd mode influence

Ray,

You mention that material dominates losses on microstrips, is this no
longer true with embedded microstrips? Is this statement true with
stripline constructions as well? I would expect it to be so.

Thanks for sending such excellent information.

Chris Heard
3Com Corp

"WAUGH,RAY (HP-SanJose,ex1)" <ray_waugh@am.exch.hp.com> on 07/19/99
07:05:05 PM

Please respond to si-list@silab.eng.sun.com

Sent by: "WAUGH,RAY (HP-SanJose,ex1)" <ray_waugh@am.exch.hp.com>

To: "'si-list @silab.eng.sun.com'" <si-list@silab.eng.sun.com>
cc: (Chris Heard/US/3Com)
Subject: RE: [SI-LIST] : even-odd mode influence

Steve...
The measurements I made on FR4 (and three other lower cost materials) were
made on microstrip lines which were five to eight inches long. What we (my
colleague Dan Swanson and I) did find is that microstrip line losses are
dominated by losses in the dielectric (rather than in the copper
conductors). As a consequence, the loss tends to be a fixed number when
expressed as dB/wavelength. See the attached PDF file.
At 10 GHz, an 18 inch FR4 microstrip line is going to be a bit lossy.
Ray
_/ Raymond W. Waugh - WSD Diode Applications
_/ E-mail: ray_waugh@hp.com
_/_/_/ _/_/_/
_/ _/ _/ _/ USPS : Wireless Semiconductor Division
_/ _/ _/_/_/ 39201 Cherry Street, MS NK20
_/ Newark, California 94560
_/
-----Original Message-----
From: Stephen Zinck [mailto:zinck@cabletron.com]
Sent: Monday, July 19, 1999 9:39 AM
To: si-list@silab.eng.sun.com
Subject: Re: [SI-LIST] : even-odd mode influence

Ray,
How long was the transmission line on this board? Have you had any success
with transmission lines on the order of 18" long (@ 10 GHz) using FR-4?
Just curious.
Thanks,
Steve

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