Return-Path: Received: (qmail 19611 invoked from network); 29 Nov 2002 11:47:25 -0000 Received: from netmail01.services.quay.plus.net (212.159.14.219) by mailstore with SMTP; 29 Nov 2002 11:47:25 -0000 Received: (qmail 21363 invoked by uid 10001); 29 Nov 2002 11:47:43 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by netmail01.services.quay.plus.net with SMTP; 29 Nov 2002 11:47:43 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18HjcE-0000rG-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 29 Nov 2002 11:47:26 +0000 Received: from [62.253.164.42] (helo=mta2-svc.business.ntl.com) by post.thorcom.com with esmtp (Exim 4.10) id 18HjcE-0000r7-00 for rsgb_lf_group@blacksheep.org; Fri, 29 Nov 2002 11:47:26 +0000 Received: from there ([217.137.95.11]) by mta2-svc.business.ntl.com (InterMail vM.4.01.03.27 201-229-121-127-20010626) with SMTP id <20021129114726.VWHU3351.mta2-svc.business.ntl.com@there> for ; Fri, 29 Nov 2002 11:47:26 +0000 From: "Steve Thompson" To: rsgb_lf_group@blacksheep.org Date: Fri, 29 Nov 2002 11:50:15 +0000 X-Mailer: KMail [version 1.3.1] References: <7D653C9C42F5D411A27C00508BF8803DCB9D07@mail.dstl.gov.uk> In-reply-to: <7D653C9C42F5D411A27C00508BF8803DCB9D07@mail.dstl.gov.uk> MIME-Version: 1.0 Message-ID: <20021129114726.VWHU3351.mta2-svc.business.ntl.com@there> Content-Type: text/plain; charset=iso-8859-1; format=flowed Subject: Re: LF: Printed Spiral Inductors - off topic Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-1.3 required=5.0tests=IN_REP_TO,QUOTED_EMAIL_TEXT,REFERENCES,SPAM_PHRASE_00_01version=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group On Friday 29 November 2002 11:13, you wrote: > Sorry if this is somewhat off topic, but I am looking for the design > equations for spiral inductors printed on PCB material, with or without a > groundplane. I vaguely remember seeing some equations in one of the > freebie RF magazines a few years ago, but can't find it. A web search has > not pointed at anything useful - yet. > > I need to design some bandpass filters in the 300MHz and 600 to 800MHz > ranges and want something more repeatable than bits of silver plated wire. > > Can anyone lay their hands on the design equations ? I have 'Broadband model predicts s-parameters of spiral inductors' from Microwaves & RF, Jan 88 which I can send if you give me an address. I also have an ancient version of Touchstone that includes a spiral inductor as an element, which you are welcome to come and use. Steve