Has anyone looked at this patent?
See
http://l2.espacenet.com/espacenet/viewer?PN=WO0245210
for details.
It's basically a coil wrapped around a ferrite rod/tube
that sensitive to the magnetic part of the electromagnetic
field.
The author claims it can be built small, handle high
power, and is mostly omni-directional.
They also went to the trouble of patenting it
in Canada, number CA2427575, but I can find no US patent.