29
AVR

The Electromagnetic Spectra of Ordinary Objects

Colloque / Congrès / Forum
Ouvert au grand public
29.04.2020 17:30
Présentiel

There is an aspect of Electromagnetics that has been somewhat overlooked. Common everyday objects can act as electromagnetic resonators. Indeed ordinary objects have a series of resonant frequencies extending from radio waves up to optical frequencies. These resonant modes can be modeled as LC circuits. Thus every object that we encounter is an LC resonator. Since LC circuits support ac currents, and since ac currents imply electron acceleration, they inherently radiate into the far-field. Therefore ordinary objects that we come across, in our daily lives, can act as electromagnetic antennas. This means that ordinary object have a Q-factor and a radiation Q-factor for each resonant mode. The lowest frequency resonance is the most characteristic of the object geometry, but there is an entire spectrum of higher frequencies to work with, different and characteristic for every object. Many of the properties that have been attributed to plasmonic resonances are actually universal, and they arise already in ordinary electromagnetics. In communications technology, the antenna application is the most important. The antennas in cellphones, carried by almost everyone on the planet, are examples of multi-frequency resonant objects, enabling wireless connectivity.
https://www2.eecs.berkeley.edu/Faculty/Homepages/yablonovitch.html
https://en.wikipedia.org/wiki/Eli_Yablonovitch
Quand?
29.04.2020 17:30
Où?
Site PER 08 / Salle Zoom Meeting
Chemin du Musée 3, 1700 Fribourg
Organisation
Département de Physique
Prof. Frank Scheffold
nadia.pury@unifr.ch
Intervenants
Prof. Eli Yablonovitch, UC Berkley
Retour à la liste
«juin 2025»
lmamejvsd
2627282930311
2345678
9101112131415
16171819202122
23242526272829
30123456