Research On Manipulation Of Electromagnetic Energy Based On Toroidal Dipoles

Toroidal dipole is an elusive dipole which has been acknowledged in nuclear,DNA and some ferroelectric systems. Although toroidal dipole is also an fundamentalelectromagnetic response, it is different from the electric and magnetic dipole andmuch more elusive. Because of its weakness response, it has been neglected for a longtime. And the parity violation of nuclear and particle physics can also reveal theexistence of toroidal dipole, but there is no experiment can prove it.Until recent years, the development of metamaterial provides us an exoticmethod to solve problems. Metamaterials can reveal the electromagnetic response thatwe cannot achieve before and make it possible to experiment and simulation abouttoroidal dipoles.A new toroidal dipole metamaterial structure is proposed in this paper to analogsimulation. Several fundamental cases of the toroidal dipoles are discussed and thecharacteristics of the toroidal dipole scatter field are described by the current on thesplit ring. For exploring the theory of the toroidal dipole, we have simulated theproposed structure unit cell. By simulation, we know the structure has two resonantfrequencies at13.692GHz and16.184GHz. For further analysis about the surfacecurrent, we can confirm that at16.184GHz, the toroidal dipole moment is a domainmoment, and at this time, electric dipole moment, magnetic dipole moment andquadrapole dipole moment have been substantially suppressed，while the toroidalresponse is resonantly enhanced to a detectable level.At the same time, when we use the circularly wave as the incident source, we canachieve the polarization twist characteristics and the structure we proposed in thispaper has double-face characteristics and very exotic chirality. For further understoodand make a foundation of the future study, we observed the S parameter by differentparameter of the unit cell.By concentrating on the polarization twist characteristics, we proposed theimproved toroidal dipole metamaterial, achieve a further efficiency of the polarizationtwist. By simulation, we can improve the polarization twist efficiency to90%. Andthe improved toroidal dipole has a four-face characteristic. At last, we have processed the toroidal dipole metamaterial and haveexperimented. We have achieved a perfect experiment result.