On 4/16/2015 3:49 PM, Erich wrote:
My first thought on this is "there is no free lunch". I have not yet
read the paper, and do not understand what they call "symmetry
breaking". However, there are two things that limit the performance of
physically small antennas. First, power density is defined as power per
unit area. This means a small capture area will capture a small amount
of power. Second, physically small antennas usually mean small
impedances. That means high currents and high I^2*R losses.
Superconducting antennas can get around some of these losses at the cost
of high complexity.
You have a common misconception of "capture area". It is NOT
the same as the physical area of the antenna. If there were
no I^2R losses, all small antennas would have a gain of 1.5
along with the corresponding capture area, regardless of
physical size.
In any event, what really limits small antennas is the very high
Q that is necessary to get good efficiency. Making the
antenna out of a superconductor doesn't fix this. You still have
very narrow bandwidth and very limited power handling.
This is per K6OIK, who really knows this stuff. See:
https://www.fars.k6ya.org/docs/k6oik#AntennaQ
Rick N6RK
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