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From: Ken
Date: 16 Jun 1999
Time: 23:40:55
Remote Name: 207.227.238.46
I haven't (yet) seen those patent references you mentioned regarding cross-wound coils. I'll comment on them later, I suppose...
I propose a definition: a Crossed Field Antenna is... an electrical structure which by design and intent utilizes _separate_ E and H field excitation mechanisms by which Poynting synthesis occurs within the volume immediate to the structure.
Conventional antennas accomplish radiation, as Hately and Kabbary suggest in their patent, by accident, via interaction starting from the reactive near-field and propagating near-field boundary. CFAs, if they were 'perfect', would never generate reactive fields; synthesis occurs by design well within these boundaries. THIS constitutes a so-called CFA. An antenna that claims crossed-field synthesis of radiation must have carefully controlled E and H field generator sources working in syncronization, even if from some single excitation source coupled through a network.
Conventional (and as far as I've seen unconventional) antennas rely still on the fact that there will be some reactive field before the fields phase properly and reactive energy will leak out and propagate. This cross-wound coil, if that's what it really is, is no exception. I think. Whatever you call it, I believe that what distinguishes a 'true' CFA from any other device is the design toward eliminating any reactive near field from the coupling mechanism between E and H.
Anyhoo, I still would like to get an inside look at this toroidal thing, whatever it is. Better yet, I'd love to see RDPs (radiation distribution patterns, for those who don't actually test antennas) over its advertised bandwidth (gain, NOT directivity, thanks). Looks interesting. But still snake oil until real data happens.
A side note to everyone else: I am currently regaining a long-lost Ham license, but in the mean time, have been actively engaged in actually designing and testing antennas for much of my career since school. I saw this CFA thing only a week ago on this site and was floored that so little apart from this forum has been published. I have spoken to a half dozen engineers within my organization: none have heard of it, but none can find anything wrong with the math. This is truly better than sliced bread. I'm amazed it hasn't caught on with IEEE and other peer organizations -- but I'm sure glad this forum is here. Hang in there, this thing has serious science!
Ken