Magnetic and Electric Excitations in Split Ring Resonators

TL;DR

This paper investigates the electric and magnetic resonances in U-shaped split ring resonators, revealing higher order modes, current distribution nodes, and how the resonances depend on the arm length, with implications for magnetic moment generation.

Contribution

It provides a detailed analysis of higher order electric and magnetic resonance modes in split ring resonators and their dependence on geometric parameters.

Findings

Higher order resonance modes exist in SRRs.

Magnetic resonances are odd-half-wavelength modes; electric are integer-wavelength modes.

Magnetic moment vanishes as side arms shorten to zero.

Abstract

We studied the electric and magnetic resonance of U-shaped SRRs. We showed that higher order excitation modes exist in both of the electric and magnetic resonances. The nodes in the current distribution were found for all the resonance modes. It turns out that the magnetic resonances are the modes with odd-number of half-wavelength of the current wave, i.e. 1/2, 3/2 and 5/2 wavelengths modes, and the electric resonances are modes with integer number of whole-wavelength of current wave, i.e. 1, 2 and 3 wavelengths modes. We discussed the electric moment and magnetic moment of the electric and magnetic resonances, and their dependence to the length of two parallel side arms. We show that the magnetic moment of magnetic resonance vanishes as the length side arms of the SRR reduces to zero, i.e. a rod does not give any magnetic moment or magnetic resonance.