Well, looks to me like my suggestion of a quarter-wave stub was right on target (I'll try not to break my arm patting myself on the back here). You have the dimensions below. Mount an SMA feedthrough connector on a circular disk of sheet metal of radius equal to or greater than the stub length, connect stub to center conductor on one side, coax from PCMCIA card on the other side, and voila. If you are using that 30 dB pad we discussed earlier (I'm still not clear on the need for that) the combination of 30 dB pad and quarter-wave stub will be so close to 50 Ohms that you would be hard pressed to measure the error.
---------- >From: Muriel Bittencourt de Liz <mur...@grucad.ufsc.br> >To: Ken Javor <ken.ja...@emccompliance.com> >Cc: Lista de EMC da IEEE <emc-p...@ieee.org> >Subject: Re: antenna and cable for 2.4GHz >Date: Tue, Dec 7, 1999, 12:20 PM > > Ken & Group, > > The data I have for this antenna are these: > > - The board is a Wireless LAN > > - The antenna must be omnidirectional > > - The output power is 100mW > > Thanks in advance for the answers > > Best Regards > > Muriel > > > Ken Javor wrote: >> >> I checked out the referenced web site. Not a whole lot of information, but I >> gleaned the following. Since the application is WAN/LAN, the antenna must >> be a low directivity broadcast type, probably a quarter wave stub or similar >> device. At 2.4 GHz, this amounts to 31 mm, or 1 1/4 ". A quarter wave stub >> looks approximately like a 35 Ohm load. Not too bad a match to 50 Ohms. I >> suppose you could shorten it up a bit to increase the load, but it becomes >> capacitive when you do that. Still not sure about the 30 dB pad. Is this >> when you are connecting together two PCMCIA cards without the intervening >> loss associated with the rf link? In any case, I don't know of any kind of >> coax that would provide 30 dB of attenuation with a reasonable length. For >> example, you would need almost 100' (30 m) of RG-58 to get 30 dB >> attenuation. Better off to use a 30 dB pad. As long as transmit power is >> low, this is a minor addition. >> >> ---------- >> >From: Muriel Bittencourt de Liz <mur...@grucad.ufsc.br> >> >To: Ken Javor <ken.ja...@emccompliance.com> >> >Cc: Lista de EMC da IEEE <emc-p...@ieee.org> >> >Subject: Re: antenna and cable for 2.4GHz >> >Date: Mon, Dec 6, 1999, 4:59 AM >> > >> >> > in detail the board details: >> > >> > http://www.mcc.com/projects > > -- > 8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-)8-) > Muriel Bittencourt de Liz, M.Sc. - EMC Engineer > GRUCAD - Group for Conception & Analysis of Electromagnetic Devices > Santa Catarina Federal University - UFSC > PO Box: 476 ZIP: 88040-900 - Florianópolis - SC - BRAZIL > Phone: +55.48.331.9649 - Fax: +55.48.234.3790 > e-mail: mur...@grucad.ufsc.br > ICQ#: 9089332 > --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
