Analysis Of Antenna Structures Research Articles

Analysis of Antenna Structure for Energy Beamforming in Wireless Power Transfer

The technology to send a magnetic field in a particular direction, known as energy beamforming, has been recently introduced as a magnetic field shaping technology in nonradiative wireless power transmission. In general, one of the most efficient conditions for energy beamforming is that the magnetic fields induced by each antenna should be synthesized to head the same direction. To synthesize the magnetic fields induced at each antenna, interference by mutual inductance that can occur between transmitting (TX) antennas should be minimized. In addition, energy should not be exchanged between the TXs, otherwise it lowers the transmission efficiencies of TX and receiving antenna. In this paper, we present an optimal antenna structure that minimizes the mutual inductance between two TX antennas. First, we have analyzed the mutual inductance between TX antennas that have asymmetric sizes with different antenna lengths and arrangement angles. The directivity of the magnetic field vector is also investigated through an experimental analysis of an antenna structure. Finally, it has been verified that the optimal TX antennas for energy beamforming should be symmetric, which means that all the length of antennas are same and disposed perpendicular to each other. The experimental results show that the deviations of magnetic field directivity for symmetric and asymmetric antennas are 0.045 and 0.355, respectively, which shows that the symmetric structure shows 8.2 times larger consistency over the asymmetric structure.

Data‐driven model based design and analysis of antenna structures

Data-driven models, or metamodels, offer an efficient way to mimic the behaviour of computation-intensive simulators. Subsequently, the usage of such computationally cheap metamodels is indispensable in the design of contemporary antenna structures where computation-intensive simulations are often performed in a large scale. Although metamodels offer sufficient flexibility and speed, they often suffer from an exponential growth of required training samples as the dimensionality of the problem increases. In order to alleviate this issue, a Gaussian process based approach, known as Gradient-Enhanced Kriging (GEK), is proposed in this work to achieve cost-efficient modelling of antenna structures. The GEK approach incorporates adjoint-based sensitivity data in addition to function data obtained from electromagnetic simulations. The approach is illustrated using a dielectric resonator and an ultra-wideband antenna structures. The method demonstrates significant accuracy improvement with the less number of training samples over the Ordinary Kriging (OK) approach which utilises function data only. The discussed technique has been favourably compared with OK in terms of computational cost.

Fast analysis of metallic antennas by parallel moment method implemented on CUDA

In this paper a modeling technique enabling the fast analysis of antenna arrangements built-up from metallic parts is presented in detail. A calculation method which accelerates the solution of integral equations discretized by the Method of Moments have been implemented in a massively parallel computing environment, a general purpose video card (GPU). Rao-Wilton-Glisson edge basis functions are used to expand surface currents, while radiated field is computed using the dipole model. Since the entire computation takes place on the GPU exclusively, the overall computational time could be significantly reduced. To obtain such an acceleration, a novel computational technique is proposed for the filling of the impedance matrix, which takes full advantage of the given platform. Analysis of antenna structures can be made very efficiently using the frequency domain (FD) integral equationformulation, discretizedby the Methodof Moments (MoM) (1). The FD-MoM implementation employing surface patch modeling (2) of the (infinitesimally thin) metal surfaces lacks the incorporation of the surrounding air. This is a major advantage over Finite Element Method (FEM), where the surrounding air is part of the model and therefore must be discretized as well. As the computational complexity (demand) is proportional to the number of discrete geometrical elements constituting the model, in the latter case the Degrees of Freedom (DoF) of the resulting linear equation system to be finally solved is significantly higher than in the preceding one. Furthermore, as the correct behavior for the radiation condition is automatically incorporated in the moment method, there is no need for special termination -by e.g., a Perfectly Matched Layer (PML) or Absorbing Boundary Condition (ABC)- of the problem domain, as in FEM. Unfortunately, the advantagesof MoM are spoiled by its well-known high demands for computational resources in terms of memory capacity and CPU time. Although spectacular reduction techniques like the so-called multi-level fast multiple Method (MLFMM) exist, these can not be applied to all practical problems, hence often the tedious standard MoM formulation is to be utilized. In this paper the acceleration of the standard MoM method is carried out using a massively parallel computing environment, the GPU. Although several similar works have already been published (3,4),

Analysis of antenna structure with equal E- and H-plane patterns

Analysis of an antenna structure which yields equal E- and H-plane patterns is presented in this paper. The structure consists of an excited slot with two symmetrically disposed and parasitically excited monopoles. The equalisation of the E- and H-plane patterns depends upon the coupling between the slot and the monopoles, which is a function of monopole height and separation from the slot. An evaluation of coupling between monople and slot is done, and an optimum configuration is obtained. The analytical results obtained as shown to be in close agreement with the experimental ones obtained by other researchers.

Analysis of antenna structures assembled from arbitrarily located straight wires

Pocklington's integral equation for a straight, slim wire element is solved for the distribution of wire current, using the Bubnov-Galerkin projective method. Interpolation polynomials are employed as approximators, and special weighted Gaussian quadratures are used to avoid difficulties in the near-singular integrals encountered. It is shown that Kirchhoff's current law, applied wherever several such wire segments are electrically connected, leads to a modification of the approximating matrix equation by elementary row and column operations. Computer programs based on this method are used to analyse several different types of wire antenna, and the results are compared with experimental data. Agreement is generally good, and computing times pleasingly low, indicating that this method is likely to be generally preferable to point-matching methods that lead to much larger matrix sizes.