Related papers: Enhanced Planar Antenna Efficiency Through Magneti…
Small volume, finite conductivity and high frequencies are major imperatives in the design of communications infrastructure. The radiation efficiency $\eta_r$ impacts on the optimal gain, quality factor, and bandwidth. The current…
We present highly sub-wavelength magnetic metamaterials designed for operation at radio frequencies (RFs). A dual layer design consisting of independent planar spiral elements enables experimental demonstration of a unit cell size (a) that…
We consider a graphene sheet encapsulated in a two-dimensional metallic grating and a substrate ($\mathrm{Al_{2}O_{3}}$) and subjected to an external magnetic field (in Faraday configuration). The grating consists of a thin perfectly…
Both the radiation efficiency and bandwidth of electrically small antennas are dramatically reduced as the size decreases. Fundamental limitations on the bandwidth of small antennas have been thoroughly treated in the past. However, upper…
This paper presents the efficient Yagi-Uda nanoantenna with the chain of directors, reflector and a feed element, where these elements have been optimized to fulfil the requirement of high directivity and the gain of antenna. The proposed…
Spatial coordinate transformation is used as a reliable tool to control electromagnetic fields. In this paper, we derive the permeability and permittivity tensors of a metamaterial able to transform an isotropically radiating source into a…
The magnetoimpedance effect is a versatile tool to investigate ferromagnetic materials, revealing aspects on the fundamental physics associated to magnetization dynamics, broadband magnetic properties, important issues for current and…
This paper presents radiation efficiency and gain bounds for microstrip patch antennas. The presented bounds are shown to be good predictors of antenna performance. Using the bounds, patch miniaturization techniques based on high…
We characterize planar electric terahertz metamaterials fabricated on thin, flexible substrates using terahertz time-domain spectroscopy. Quasi-three-dimensional metamaterials are formed by stacking multiple metamaterial layers.…
We experimentally demonstrate at terahertz frequencies that a planar metamaterial exhibits a spectral response resembling electromagnetically induced transparency. The metamaterial unit cell consists of a split ring surrounded by another…
Influence of applied in-plane elastic strains on the static magnetic configuration of a 530 nm magnetostrictive FeCuNbSiB thin film. The in-plane strains are induced via the application of a voltage to a piezoelectric actuator on which the…
This study investigates the possibility of increasing the radiation efficiency of printed antennas and arrays by suppressing their inherent surface waves using a metasurface made of quad-split rings (QSR). A symmetrical resonant microstrip…
Existing optimization methods are used to calculate the upper-bounds on radiation efficiency with and without the constraint on self-resonance. These bounds are used for the design and assessment of small electric-dipole-type antennas. We…
The monopole antenna is widely used in communication applications and is typically mounted on various surfaces that act as ground planes; a prime example being the roof of a car. The shape of the ground plane can drastically change the…
We demonstrate control of magnetic domain structures in continuous FePd thin films by patterning their surfaces with plasma treatment. The Fe-oxide layer formed on the surface upon ambient exposure of the FePd alloy thin film grown on an…
The magnetic shield plays an important role in magnetic near-field control. However, the requirements of efficient, ultrathin, lightweight and cheap are still the challenges. Here, we firstly propose a composite metamaterial in which the…
We show that under proper conditions thin films structures behave like thermal sources that are able to emit radiation in well defined directions over a broad spectral band for both polarization states of light. This effect results from the…
An effective approach to improve the detection efficiency of nanoscale light sources relies on a planar antenna configuration, which beams the emitted light into a narrow cone. Planar antennas operate like optical Yagi-Uda antennas, where…
Metamaterials-or artificial electromagnetic materials-can create media with properties unattainable in nature, but mitigating dissipation is a key challenge for their further development. Here, we demonstrate a low-loss metamaterial by…
We address the question of the optimal choice of loading material for antenna miniaturization. A new approach to identify the optimal loading material, dielectric or magnetic, is presented for resonant antennas. Instead of equivalent…