Experimental Verification of Isotropic Radiation from a Coherent Dipole Source via Electric-Field-DrivenLCResonator Metamaterials

Abstract

It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator's gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.

Inhomogeneous field in cavities of zero index metamaterials

“…Hence, the cavity structure can also be used to realize power combination3233. All in all, the proposed cavity structure exhibits much advantage on controlling EM radiation of sources, as compared with previous works333435363738 in which different devices are based on special sources.…”

Flat designs of impedance-matched nonmagnetic phase transformer and wave-shaping polarization splitter via transformation optics

“…For comparison, the parameters determined by Eq. (14) are also shown in (b) if a dielectric-magnetic slab is used to implement the same function.…”

“…For comparison, if a dielectric-magnetic slab is used to implement the same function, the parameters determined by Eq. (14) are shown in Fig. 4(b) as well.…”

“…Employing this method, a host of striking electromagnetic devices have been demonstrated [3][4][5], the first of which was the invisibility cloak [6]. Following the cloak was a large body of work devoted to controlling the path of light rays resulting in beam shifters [7], beam bends [8][9][10], and wave scaling devices [11][12][13][14][15]. By combining two beam shifters for TE and TM waves into one device, a polarization splitter was achieved [16,17].…”

A dielectric-only superstrate inspired from transformation optics for complete reorientation of electromagnetic waves in azimuthal plane

“…Under appropriate design conditions, the contribution of permeability values in profile can be ignored and it may be interpreted using only permittivity values [15][16][17]. A purely dielectric profile is much easier to realize in fabrication using either electric-field-driven LC (ELC) resonator structures [18][19][20][21][22] or using isotropic standard dielectric materials [23]. An ELC resonator is a metallic pattern lithographically printed on a substrate that is capable of providing a strong electric response.…”