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A rapid solution for evaluating the radiation pattern of aperiodic arrays, taking into account mutual coupling, is presented in this paper. The evaluation is achieved by eliminating the anisotropy of the active element pattern of the array through the use of the mutual coupling compensation matrix (MCCM) technique, in conjunction with the non-uniform fast Fourier transform (NuFFT). In order to eliminate the impact of mutual coupling on array pattern calculation, the MCCM is utilized to convert the active element pattern (AEP) of each element into a shared uniform term and make the NuFFT technique suitable for the array pattern calculation. The proposed solution is validated by evaluating the radiation pattern of a 64-element planar aperiodic array. In addition, the proposed solution is integrated into the Particle Swarm Optimization (PSO) to realize a pattern synthesis method. Two synthesized patterns, including a pencil beam with low sidelobe level and a flat-top beam pattern, are executed to validate. Compared with several reported methods, the proposed method can improve the synthesis efficiency and maintain good accuracy simultaneously.

This paper presents a novel technique based on Hybrid Spatial Distance Reduction Algorithm (HSDRA), to compensate the effects of deformity and mutual coupling occurred due to surface change in conformal arrays. This antenna surface deformation shifts the position of null points and loss of the main beam resulting in reduced antenna gain along with substantial undesirable effects on the antenna performance. The proposed algorithm, which cumulatively incorporates the Linearly Constraint Least Square Optimization (LCLSO) and Quadratically Constraint Least Square Optimization (QCLSO) techniques, is formulated to minimize/reduce the absolute distance between the actual (simulated/measured) radiation pattern and the desired radiation pattern while keeping the direction of main beam and nulls position under control. In particular, a 4x4 conformal microstrip phased array from planar surface is deformed to prescribe spherical-shape surface with various radii of curvature, is validated. For the enhancement of Gain of the conformal array antenna, Gain Maximization Algorithm is also proposed, the simulated results of which is compared to the traditional Phase compensation technique and unconstraint least squares optimization. The analytical results for both planar and spherical deformed configurations are first evaluated in MATLAB and then validated through Computer Simulation Technology (CST).

In this paper, the effects of mutual coupling and antenna surface deformity in a conformal wedge-shaped antenna array are compensated using a linear pattern correction technique. The problem is formulated to reduce the absolute distance between the actual (simulated) and the desired radiation patterns and to allow for null positioning control. The individual field patterns for the antenna elements are deformed due to changes in mutual coupling and the conformal surface. The deformed patterns of the individual antennas for specific bend angles are stored as lookup tables and interpolated to get the desired radiation pattern at any arbitrary bend-angle. The problem is linearly and quadratically constrained at the null points and performance compared with unconstrained optimization. The proposed solution for diminishing the effect of mutual coupling and surface deformity is independent of main lobe direction, type of individual antenna, array geometry, and spacing between antenna elements. The closed-form results are validated through Computer Simulation Technology (CST) for the wedge-shaped deformed dipole antenna array. The results for the proposed scheme are also assessed with the traditional Open Circuit Voltage Method (OCVM) and show superior compensation for deformity and the mutual coupling effects in conformal beam-forming arrays in terms of main beam direction, position and depth of nulls.

This work presents the design, simulation and implementation of a linear array antenna with a fully constrained cosecant squared radiation pattern and a novel wideband feeding network. This antenna is constructed of wideband printed dipole antennas as the array elements in which the mutual coupling effect is properly compensated. For this purpose, a constrained particle swarm optimisation (PSO) algorithm is used as the synthesis method which is able to deal with multiple constraints in the desired radiation pattern. The excitations obtained from the PSO algorithm are applied to the design of a wideband feeding network which is able to deliver stable phase shifts and output powers to the array elements over the desired bandwidth. Finally, the simulation results are confirmed by the measurement results.

The performance of an antenna array is considerably affected by mutual coupling effects between antenna elements. When a large number of antenna elements are located close to each other, mutual coupling becomes more significant. In this study, by using a new mutual impedance matrix, a decoupling methodology for compensating mutual coupling effects in a practical very high frequency (VHF)/ultra high frequency (UHF) Yagi-Uda antenna array is introduced. No previous publications have studied VHF/UHF Yagi-Uda antenna arrays in this context. In the proposed scheme, extreme care has been taken to account for both self- and mutual impedance related to mutual coupling effects. Experimental and simulation results show that using the proposed method, a perfect decoupling is achieved. The application of high-resolution direction of arrival (DOA) estimation algorithms in decoupled experimental data leads to excellent performance of DOA estimation, in terms of accuracy and resolution. In addition, it is concluded (from experimental and simulation results) that mutual coupling effects between array elements as well as the root-mean-square error of estimated parameters depend on the direction of arrival. It is also deduced that in the presence of mutual coupling, estimation of signal parameter via rotation invariance techniques algorithm performs better than other subspace-based algorithms.

In a recent study by Niow et al., it has been shown that an effective method for mutual coupling compensation in antenna arrays can be based on mutual impedances between antenna elements and the active element input impedance. Consequently, Niow et al. have derived an equation for compensated excitation voltages, which allows the radiation pattern of an antenna array to be predicted accurately using the principle of pattern multiplication. In the current comment, the authors show that the effectiveness of those equations depends on the level of mutual coupling between radiating elements, and becomes lower for strong mutual coupling. The authors explain the reason for this deficiency and a corrected form of the equations was proposed for the compensated excitation voltages.

In dynamic magnetically coupled contactless power transmission, the fluctuation of mutual inductance is caused by the relative motion between transmission and receiving coils, which affects the stability of power transmission. In order to reduce the fluctuation characteristics of power transmission, the mutual inductance calculation model of transmission mechanism including a racetrack coil with deflection angle is established by using Neumann formula, and the influence of different deflection angle and layout on mutual inductance fluctuation characteristics is analyse and compare. Then the power transmission system with LCC-S compensation for the transmission mechanism is established. The transmission characteristics of the racetrack coil with deflection angle are studied. The results show that reasonable design of the deflection angle can reduce the fluctuation of the mutual inductance and the power output in dynamic transmission. The fluctuation of power output can also be reduced by changing the distance between transmission coils and the length of straight side of receiving coils.

When a distance relay protects a transmission line located on a dual circuit tower, a coupling effect will occur between the two circuits. Transposition of the circuits can reduce the mutual impedances, but this does not cater to the zero-sequence mutual coupling impedance during earth faults. As a result, the impedance measured by a distance relay under phase-to-earth fault conditions in these circumstances will not represent the correct impedance to the fault point unless these effects are taken into account. On multi-circuit lines, primarily if they operate in parallel, a zero-sequence mutual coupling should be considered when calculating settings for distance protection function. A 220 kV parallel line sharing the same tower was analysed using DigSilent Power Factory in the simulations. Phase-to-earth faults in different configurations were analysed on this system, and the reach of the protection relay was then estimated for operation. The results confirm how a protection relay can overreach and underreach in a distance protection scheme due to the influence of mutual coupling.

The design characteristics of the hexagonal coil structure used as the transmitter and receiver coil pad for wireless power charging in an electric car are described in the study. Two resonant coupling coils' energy loss determines the wireless charging system's transmission power and efficiency. How many turns the transmitter and receiver coils have, as well as their size and form, impact the energy efficiency. Coupling efficiency can be increased with better designs that have coil layouts that are optimized. This paper investigates the primary factors affecting the characteristics of WPT systems: inner coil radius, coefficient of coupling, self-inductance, mutual inductance and number of turns. The intricacy of these parameters calls for finite element analysis (FEA) using the Ansys Maxwell pro-gram. The primary parameters of the WPT systems can be used to conduct an analytical calculation of the self- and mutual inductance. This coil design is validated using resonant inductive wireless charging in MATLAB tool and efficiency can be calculated. Magnetic field leakage has been studied. Here, SS compensation method and LCC-LCC topology is utilized for designing magnetic resonant coupling. The international guidelines can be ensured by the design and operation of both topologies.

Mutual coupling compensation in uniform linear and circular receiving antenna arrays of thin wire dipoles is presented. It was observed that the mutual impedance is independent of the incident angle and depends solely on the geometry of the array. By using only one measurement, decoupling matrix is computed and direction of arrival is estimated.