In my opinion, the only broadband antenna truly optimized for this use at 1 meter separation is the biconical. It is not as efficient as a dipole tuned to a specific frequency, but there are no high power baluns for dipoles and of course the dipole has to be constantly tuned.
I personally don't care for the various electric field generators available for use because they tend to be not much more than a step-up transformer that puts a high potential on the "radiating elements". But the elements really don't radiate much power, rather they set up a fringing field which is almost totally electric, i.e., very high impedance. Most circuits these days aren't particularly sensitive to pure electric fields. The biconical, in this frequency range, actually launches a traveling wave. I'm not saying it is a 377 Ohm plane wave one meter away but I expect it is much closer than you get >from other sources. I also looked at a log periodic array used from 80 MHz on up. It gives similar performance to the biconical below 200 MHz. It might be slightly better, but if you don't already have one and you have a biconical it's hard to see why you would want the log periodic, based on sub-200 MHz performance alone. If you have a really small test item, you can't beat a parallel plate for Volts per meter per Watt efficiency and also for the purity of the 377 Ohm guided wave launched down the length of the plate. The test sample needs to be no larger than lambda/10, so for 200 MHz you are looking at a cell phone sized device. From: "Derek Walton" <[email protected]> Organization: L F Research List-Post: [email protected] Date: Wed, 7 Dec 2005 00:21:14 -0600 To: "IEEE EMC Discussion Group" <[email protected]> Subject: Antenna fro RS testing from 100 MHz to 200 MHz HI Folks, I'm looking for an antena optumised for transmitting inside a shield room from 100 MHz to 200 MHz, does anyone have suggestions on what design I could use? Ideally the antenna should be polarised... -- Cheers, Derek Walton L F Research Poplar Grove, IL 61065, USA - --------- ------------------------------------------------------ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
