Re: NEC-LIST: Negative driving point impedances in phased arrays

John Belrose <john.belrose_at_crc.ca> writes:
>
> Jim, negative input impedances frequently occur in phased array
> (MF
> broadcast) antenna systems. Another example is given in my
> chapter
> on VLF, LF and MF Antennas [1], pp. 614-615. This is because you
> are
> using multiple fed the antenna system. --- two or more sources.
<snip>
> John S. (Jack) Belrose
>

And, presumably in such cases, one can't use a separate power
amplifier for each element, since, by and large, amplifiers
won't work to turn RF power back into DC bus power. It's an
interesting idea.. it's used in power engineering - 4 quadrant
motor controllers do it, for instance.

Perhaps, if one has a system with nonreciprocal devices in the
feeds (i.e. a power amp on each element), that implies some
constraints on the types of beams that one can form.

Jim Lux

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