Thanks Charles! That's a super app note! Gotta figure if *they* got it to work that way, I have a chance at it! Jim ----- Original Message ----- From: "Charles Craft" To: Sent: Wednesday, June 23, 2004 1:08 PM Subject: Re: [EE:] Circuit Board Loop Antenna? > http://ww1.microchip.com/downloads/en/DeviceDoc/70093a.pdf > > You don't want a copper pour under the antenna. > Check out pages 27 and 28 of the doc above. > > Steven Bible did the rfPIC sessions at the 2002 and 2003 MASTERs. > Search on his name at the Microchip web site and you'll find a half dozen white papers on RF stuff. > (http://tinyurl.com/3b2zl) > > http://ww1.microchip.com/downloads/en/DeviceDoc/prt5.pdf > This whitepaper has plenty o' math to make my head spin. Might help you. > > > -----Original Message----- > From: Jim Tellier > Sent: Jun 23, 2004 3:30 PM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [EE:] Circuit Board Loop Antenna? > > Harold Hallikainen wrote: > > I'm working on an RFID project and need to make a 208uH loop antenna. I'd > > like to try to do it as a rectangular spiral trace on a circuit board. Can > > anyone suggest a resource on calculating the inductance of such an > > inductor? > > Harold, > Are you by any chance doing something with an RFPIC device? They have an > appnote (AN831 = Matching Small Loop Antennas to RFPIC devices", or similar > title); I've not read it (yet), but it may contain something useful. I'm > also starting a project of that type with a RFPIC12F675, and thought about > doing the pcb trace thing as well. In uChip's device sheet for the '675, > they illustrate a schematic using a "loop antenna" but they don't spec its > inductance :^( I thought that was kind of lame; I can't imagine it's not > critical at ~480MHz! > I'm still working on a Eagle layout for my project (which is both my first > RFPIC project AND first surface-mount pcb... woo-hoo!), and was planning on > using a full copper pour ground plane on side 2. I wonder how that will > affect the idea of a spiral loop ant on side 1? I imagine it would result > in a hugely directional emitter, wouldn't you think? > I'll look forward to moving ahead with this as soon as I too get some > questions answered! > Jim > > > > -- > > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body