The phonons' energy of the 'metal of antenna' and also that 'of reflector metal' can be increased or decreased by heating or cooling. If transmission or reflection is of EM wave with frequency of 'the order close to that of phonons' e.g. millimeter, microwaves or IR rays then is it possible that phonons' energy of the transmitter is superimposed over the transmitted waves. Similarly in case of reflector can the phonons' energy be superimposed over the reflected waves?
Interesting question Prof. Prabhat Kumar, but at least for me the physics is unclear, do you mean anomalous thermal radiation in an antenna?
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The skin effect in metals also produces thermal waves, it was investigated theoretically in the 90s. I just cannot recall everything.
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Also, there is a phonon radiation effect in metallic films:
https://hal.archives-ouvertes.fr/jpa-00215079/document
Best Regards.
You would somehow need an efficient converter from EM waves into phonons. For (very) high EM field levels there are thermoacoustic effects where e.g. for pulsed EM radiation a small part of the EM energy is converted into acoustic shockwaves which can of course only take place in lossy materials.On the other hand phonons can siomply be created by the radiation pressure of the RF EM field.
Observation, and penetration depth are taken into account in the field of electromagnetic waves.
This converts phonons to energy in a communications signal, but by modulating a higher frequency signal, I think. It may be a step towards what you are thinking of.
Dear Pedro L. Contreras E. , I think an amplification of RF microwave phonon means the conversion of heat energy loss of the antenna into the electromagnetic wave. Using acoustic phonon, we can collect the heat energy which is considered as the loss of heat energy and finally convert it into electromagnetic energy using optical phonon.
https://www.quantiki.org/wiki/phonon
Thank you so much for the nice explanation, Prof. Pankaj Chandra Kar
Best Regards.
Dear Prabhat Kumar ,
Phonons are the quantum of the thermal energy in the materials. These phonons interact with the free electrons in the material and consequently the electrons acquire thermal random motions like the motions of the gas molecules.
This is called the thermal noise currents. As these currents are varying with time then they will emit radiation from the antenna. If the antenna is provided by resonance circuit then only the frequency component of the noise with the resonance frequency will be effective in emanating radiation from antenna.
Accordingly since the thermal noise is white, you will find always a radiation from the antenna with its resonance frequency caused by noise. However, this will be unwanted signal.
Best wishes
The room temperature (300K) excitations correspond to roughly 10 um wavelength which is much shorter than even mm-waves. However, at optical frequencies one can observe I guess something similar: it is called plasmonic Raman scattering and causes slight up/down conversion of optical or infrared photons.
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