"Jim Lux" wrote in message
...
One wants to be careful about "Q" and Chu, etc. If you haven't actually
read the paper, you might think that Chu is talking about Q as in filter
bandwidth (e.g. center frequency/3dB bandwidth), but it's not.

I read it well over a decade ago. I like to think I've learned a fair amount
since then, so I should probably go back and do it again some time...

I had McLean as a professor as an undergraduate -- he was already ruminating
about Chu not having the full story back in the early '90s, several years
prior to his (apparently pretty regularly referenced) paper on the topic on
'96
(http://www.physics.princeton.edu/~mc...44_672_96.pdf).
(He was also a fan of Goubau antennas and wanted me to help him figure out
just how they worked... I never managed to contribute anything of use towards
that end and graduated and moved, but I did visit him a few years later at
which point he told me it'd really been rather more difficult to figure out
then he'd first thought. Harumph! I do think it's cool that it eventually
ended up on a cover of a book:
http://www.amazon.com/Electrically-S.../dp/0471782556 )

It's the ratio of energy stored in the system to that radiated/lost. For
some systems, the two are the same, but not for all.

Something like... it's exactly true of a simple RLC network (2*pi*total stored
energy/energy lost per cycle)... but one can concoct fancy, higher-order
networks where it isn't exactly correct?

---Joel