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A dual-linearly polarized, electrically small, low-profile, broadside radiating Huygens dipole antenna is presented, that is, an advanced combination of electric and magnetic near-field resonant parasitic elements. Its prototype was fabricated and tested. The measured results are in good agreement with their simulated values. At 1.515 GHz, the prototype is electrically small ( $ka = 0.904$ ) and low profile ( $0.0483\lambda _{0}$ ). It exhibits high port isolation and a large front-to-back ratio (FTBR). The isolation between its two ports is demonstrated to be over 25.8 dB within its −10 dB fractional impedance bandwidth, 0.46%. When port 1 (port 2) is excited, the peak realized gain is 2.03 dBi (2.15 dBi) strictly along the broadside direction with a 12.4 dB (12.1 dB) FTBR. [ABSTRACT FROM AUTHOR]

The high coupling coefficient of a wireless charging coupler can improve the transmission efficiency. To obtain a higher coupling coefficient of double D (DD) coupler, the equivalent magnetic circuit and the expression of coupling coefficient are derived, giving some guidance for magnetic core optimization. A new core structure is designed and optimized for DD coils, and its performance is verified by 3-D finite element method simulation and experiments. Finally, a universal process is described to design and optimize core structures for different wireless charging couplers. [ABSTRACT FROM AUTHOR]

We demonstrate a technique to fabricate large-area, highly ordered CoPt antidot arrays with perpendicular orientation. Using ultrathin anodic aluminum oxide (AAO) templates as a dry etching mask, the pattern of the pore array was transferred to the film without deteriorating the magnetic properties, in particular coercivity and preferential perpendicular orientation. The size, spacing, and density of the nonmagnetic nano-columns within the CoPt antidot arrays can be adjusted by changing the fabrication parameters of the AAO templates. The nano-columns can serve as pinning sites, impeding the magnetic domain wall motion, which can influence the magnetic properties of the film. The magnetic properties of the antidot arrays depend sensitively on the antidot morphology. The coercivity ( Hc ) of the CoPt antidot array with a pore density of 2.6\times 10^11 in ^-2 fabricated using the AAO template anodized at 20 V is increased from 9.2 to 12.5 kOe due to the existence of such pinning sites. [ABSTRACT FROM AUTHOR]

Large-area magnetic antidot arrays are prepared by depositing FePt on porous anodic alumina (PAA) templates. The pore density ( \(\rho \) ), diameter \((D)\) , and interpore distance \((d)\) of the fabricated antidot arrays all can be tuned by the PAA templates. The nanopores can serve as domain-wall pinning sites, which affect magnetic properties of the samples. The magnetic properties of antidot arrays depend sensitively on the antidot morphology, such as \(D\) , \(d\) , and film thickness. Both perpendicular and parallel coercivity \((H_{c})\) increase monotonically with increasing the density of pores. Keeping the \(\rho \) constant, both \(H_{c}\) first increase with \(D\) , until a maximum is reached at a critical \(D\) . Further increasing pore diameter leads to a decrease in \(H_{c}\) . The pinning effect on FePt with different thicknesses is also investigated. [ABSTRACT FROM PUBLISHER]

Different Ni 1-D nanostructures were fabricated in various porous anodic alumina templates by electrodeposition, including Ni nanochains containing grains with diameters of 15 nm, Ni nanowires with diameters of 50 nm, and Ni nanotubes with outer diameters of 240 nm. The magnetic properties are strongly dependent on the morphology and size of Ni nanostructures. Ni nanochains have no obvious easy axis direction and present a very small coercivity. The easy axis of Ni nanowires is oriented parallel to the wire axis, and the effective magnetic anisotropy is mainly from shape anisotropy. For Ni nanotubes, easy axis is perpendicular to the tube axis, which is dominated by the magnetic dipole interaction. The angular dependence of the coercivity indicates that the weakly coupled nanoparticles within the Ni nanochains reverse their magnetization nearly independently, however, for Ni nanowires, magnetic reversal process is dominated by localized quasi-coherent nucleation mode, and Ni nanotubes show a complicated reversal behavior. [ABSTRACT FROM PUBLISHER]