Hiding and absorbing the power emitted by a dipole at the interface of an indefinite medium

The power emitted by a dipole at the interface between an indefinite (hyperbolic) medium and an isotropic medium is analyzed. The theoretical estimation is performed by using a transmission line method for time-harmonic fields in layered isotropic materials. The indefinite medium can be constructed in different ways; here we analyze, as an example, the case of alternating two subwavelength layers of isotropic materials. We compute the power spectrum of transverse electric and magnetic (TE and TM) waves and show that the power emitted by the dipole is mainly coupled into the indefinite medium underneath, opening up several application scenarios, such as innovative carpet cloaking implementations and super absorbers. © 2012 IEEE

Hiding and absorbing the power emitted by a dipole at the interface of an indefinite medium

The power emitted by a dipole at the interface between an indefinite (hyperbolic) medium and an isotropic medium is analyzed. The theoretical estimation is performed by using a transmission line method for time-harmonic fields in layered isotropic materials. The indefinite medium can be constructed in different ways; here we analyze, as an example, the case of alternating two subwavelength layers of isotropic materials. We compute the power spectrum of transverse electric and magnetic (TE and TM) waves and show that the power emitted by the dipole is mainly coupled into the indefinite medium underneath, opening up several application scenarios, such as innovative carpet cloaking implementations and super absorbers. © 2012 IEEE

Directive radiation of a line-source inside an anisotropic material slab via transformation electromagnetics

A transformation electromagnetics technique for transforming a cylindrical wave into a plane wave is provided. The electromagnetic material parameters in the final coordinate space require only a single spatially varying term of the permittivity tensor for converting the wave front of TE waves. The detailed derivation of the spatially varying constitutive parameters and matching conditions for the plane wave are provided. An example case with a magnetic current line source is reported and the proposed final antenna is proved to be directive using full wave simulations. © 2013 IEICE

Wideband Planar Transmission Line Hyperbolic Metamaterial for Subwavelength Focusing and Resolution

We analyze both theoretically and experimentally subwavelength focusing by using a planar hyperbolic metamaterial (HM) at microwave frequencies. The proposed HM consists of microstrip transmission lines (TLs) loaded by lumped components and exhibits a very flat wave vector iso-frequency dispersion diagram over a wide frequency range, and thus able to transport spectral component with large wavenumbers. This flatness is here exploited to provide subwavelength focusing with a full width half maximum (3-dB power width) of about λg/31 and λg/ 19 at 0.5 and 1 GHz, respectively, where λg is the guided wavelength in the TL microtrip grid. Numerical simulation results are in good agreement with measurement ones. Moreover, we also investigate the capability of the proposed HM to resolve sources with subwavelength distance of about λg / 6 and λg / 3 at 0.5 and 1 GHz, respectively

Wideband Planar Transmission Line Hyperbolic Metamaterial for Subwavelength Focusing and Resolution

We analyze both theoretically and experimentally subwavelength focusing by using a planar hyperbolic metamaterial (HM) at microwave frequencies. The proposed HM consists of microstrip transmission lines (TLs) loaded by lumped components and exhibits a very flat wave vector iso-frequency dispersion diagram over a wide frequency range, and thus able to transport spectral component with large wavenumbers. This flatness is here exploited to provide subwavelength focusing with a full width half maximum (3-dB power width) of about λg/31 and λg/ 19 at 0.5 and 1 GHz, respectively, where λg is the guided wavelength in the TL microtrip grid. Numerical simulation results are in good agreement with measurement ones. Moreover, we also investigate the capability of the proposed HM to resolve sources with subwavelength distance of about λg / 6 and λg / 3 at 0.5 and 1 GHz, respectively

Subwavelength focusing and resolution with hyperbolic transmission line metamaterial

We show the potential of using two dimensional hyperbolic metamaterials (HMs) made of microstrip transmission line (TL) grids loaded by lumped components for achieving subwavelength focusing and resolution at microwave frequencies. The designed planar HM exhibits a very flat wavevector-dispersion diagram over a wide frequency range, signature of the so-called canalization regime. The canalization regime allows us to transfer the field profile of a single point source at the interface through the HM, with full width half maximum of λg / 69, where λg is the guided wavelength in the isotropic TL grid at 200 MHz. We also report the ability to resolve two point sources with subwavelength distance of λg / 15. © 2013 IEEE

Subwavelength focusing and resolution with hyperbolic transmission line metamaterial

We show the potential of using two dimensional hyperbolic metamaterials (HMs) made of microstrip transmission line (TL) grids loaded by lumped components for achieving subwavelength focusing and resolution at microwave frequencies. The designed planar HM exhibits a very flat wavevector-dispersion diagram over a wide frequency range, signature of the so-called canalization regime. The canalization regime allows us to transfer the field profile of a single point source at the interface through the HM, with full width half maximum of λg / 69, where λg is the guided wavelength in the isotropic TL grid at 200 MHz. We also report the ability to resolve two point sources with subwavelength distance of λg / 15. © 2013 IEEE