The Non-Radiating Antenna
physicsworld.com
physicsworld.com
So this should work well for a near-field coupling device, but not as some kind of distant silent receiver.
The "macroscopic atom" analogy makes me wonder, because atoms can absorb traveling photons just fine. But then again, only as well as they also radiate.
You can envision some radiation pattern from far away antennas which have overlap with the near-field modes. As a consequence, some amount of energy will be received by this antenna. Naturally it depends on how well the near-field mode is excited as to how much coupling occurs.
If A doesn't produce any field at B, then it doesn't seem possible that the field B produces at A could be absorbed by A. Thermodynamics should guarantee this, otherwise you could use it (in a roundabout way) to violate the second law.
Very unclear article. A single animation would have helped massively.
https://dl.acm.org/doi/pdf/10.1145/3300061.3300120
Possibly the reduced far field radiation could enhance the security, kind of a "cone of silence" for radio, making long distance attacks even less likely.
Not the same effect, and not an analogy; it's more about the history of non-radiating accelerating charges. When it was first understood that hydrogen was composed of a positive nucleus and an orbiting electron, there was quite a bit of head scratching as to how the electron orbit was stable and didn't just radiate its orbital energy away.
Bohr's model was somewhat ad hoc, but it said that the only allowed orbits would fit integral numbers of the electron's wavelength and would not radiate its energy away. The model got the right numbers for the orbital energies so it explained the spectral lines of hydrogen, though details of the hydrogenic orbitals would have to wait until Schrodinger's equation.
What new understanding should I be getting from this new design?
That maybe opened a new perspective to me, thinking of the a coaxial as an antenna shielded by the coat, instead of just a different way to have two conductors in one cable. I don't know if this difference means anything since the signals that travel though it are typically waves around 0.
This maybe interesting to someone: While I worked in the field with a radio technician I'm fairly certain I heard that the (or maybe just one?) way they make radio work in tunnels is by stretching a coaxial signal cable with small slits through it. That kind of fits very well with how I understood it above.
(While I have studied basic electronic engineering I'm not a radio technician myself so if this doesn't sound right, please correct or fill in. Also, according to the technician I worked with antennas are really interesting, at one point he pointed out that he had laughed at what later became his favourite antenna because his first thought was that it "obviously" could not work.)
They've discovered a new form of metaball?
How do I calculate this?
Now take one dipole and insert a 1/2 wavelength delay (an additional resonator), and you end up with the same. So what they have done is synthesize the second dipole with the disk, so two dipoles along a common axis rather than parallel.
Dipole near fields drop off at 1/r^3, so yes, this is a method of near field coupling for power transfer or localized beating.
The lack of radiated energy means the real part of the impedance must be zero (or close to it?) There's some energy being stored, but no guesses as to sign of the imaginary part.