Model Of Antenna Array Research Articles

Positional Modulation Design Based on Multiple Phased Antenna Arrays

Traditional directional modulation designs are normally based on a single phased array, with the assumption that eavesdroppers and desired users are in different directions. However, it is not always the case, as it is possible that they are in the same direction. As a result, signals received by eavesdroppers will be approximately the same as desired users. To solve the problem, a multiple antenna array model is introduced, and the principle of the design is that the eavesdropper located in the same direction as the desired user for one antenna array may not be in the same direction for another antenna array. Based on such a model, in this paper, a power minimization constraint for the design is proposed, and an artificial noise component is included, resulting in a scrambled phase response for eavesdroppers. Beam pattern, phase pattern, and bit error rate are used as metrics to show the effectiveness of the designs based on multiple fixed antenna arrays and location optimized antenna arrays, respectively.

Mutual Coupling Compensation in Receive-Mode Antenna Array Based on Characteristic Mode Analysis

In this communication, the characteristic mode analysis (CMA) is applied to the analysis of mutual coupling in a receive-mode antenna array with geometric symmetry. Because CMA provides modes that incorporate a mutual coupling effect, CMA can be used to develop a method for compensating this mutual coupling effect. An understanding of the symmetries and underlying physical characteristics of the characteristic modes (CMs) of a receive-mode antenna can be used to intuitively explain the effects of incident signal polarization and incidence angle on the port signal. Using this knowledge, a mutual coupling compensation matrix (MCCM) is constructed by finding the CMs and Z-matrix of a metallic antenna array through a single simulation. The proposed method is validated by comparing MCCM-predicted with simulated port currents on a 1-D linear bowtie antenna array model. Further validation revealed that the proposed MCCM significantly reduced the compensation error and outperformed the commonly used open-circuit voltage-based MCCM in providing accurate direction-of-arrival estimation results.

Methods beamforming adaptive digital array and their study using a computer model

The article describes the computer model of an adaptive digital antenna array. We considered in detail its features and specifications. The results of experimental research methods beamforming digital adaptive antenna array using a computer model. We studied four methods of providing independent beams forming the directivity pattern, calibration of the receiving channels, interference suppression and measurement navigation parameters.

Directions of arrival optimization method for broadband antenna array based on filter bank

This paper proposes an estimation method of the directions of arrival (DOA) for the broadband signals received by a uniform planar antenna array including the mutual coupling effect. The process modeling of antenna array receiving dynamic signal is obtained accurately via building the array system electromagnetic space-time model, and the mutual coupling effect is included in the synthesis procedure automatically. The broadband signal is divided into several sub-bands, and the complex weight of these sub-bands frequencies is figured out using the least mean square iteration programming. In the proposed method, the mutual coupling effect is compensated at the different frequencies. The calculation results show that the method is suitable for the uniform linear and uniform circular array pattern integration, and it is commendably satisfied with the requirement of engineering design.

Anti-jamming antenna array model for satellite navigation equipment

The paper introduces the brief results of modeling an antenna array designed to be used as part of anti-jamming satellite navigation equipment. The study describes the procedure for calculating the weight coefficients of the antenna array based on the orthogonalization of signal and jamming spaces. According to the weight coefficients found, the resultant antenna patterns are plotted. Findings of the research show the results of how the depth of sample accumulation influences the effectiveness of adaptation to the jamming environment

A Large Antenna Array for Ka-Band Satcom-on-the-Move Applications—Accurate Modeling and Experimental Characterization

We present the accurate modeling and analysis, followed by experimental validation, of a 1024-element (64-by-16) antenna array. This fixed-beam array radiates linear polarization in Ka-band (19.7–20.2 GHz). It acts as a first step in the design and modeling of future antenna arrays for satcom-on-the-move applications. Accurate prediction of the behavior of such a large array is a challenging task since full-wave simulation of the entire structure cannot be considered. By taking advantage of existing formalisms on periodic arrays and by using appropriate methods to efficiently exploit such formulations, it is possible to accurately define the performances of all building blocks, from the feeding circuits to the radiating elements, over a frequency range. Such a detailed design also allows an accurate physical analysis. It has been successfully used to guarantee the measured performances. This paper is intended to detail different steps to antenna designers.

Simulation of Single-target Three-dimensional Localization Using Multi-channel Antenna Arrays

Three multi-channel ultra wideband (UWB) radar structures that can detect and locate single human target is proposed. The target three-dimensional localization mathematical models of different antenna arrays are constructed. The feasibility and the accuracy of these systems are verified by computer simulation. The impact factors, such as the distance between transmit and receive antenna, the number of data’s effective digits, and so on, are discussed. The results and conclusion in this paper can serve as reference for the research and development of target threedimensional localization life detection radar in the future.

A SET OF THE SPECIALIZED SOFTWARE FOR ANALYSIS AND SYNTHESIS OF AESA

The issue of expediency of application of in-house specialized software in resolving problems of design of antenna devices is reviewed. The functional capabilities of existing software models of antenna arrays have been analyzed. The application of the developed software in designing a whole set of tasks for the adoption of basic design and engineering solutions at the stage of design of active phased antenna arrays as well as at the state of their upgrade is substantiated. The developed software has an intuitive user-friendly interface adapted to a specific set of tasks. As an example, a description is given of a set of developed software models for the study of equidistant linear and two-dimensional antenna arrays, as well as non-equidistant arrays. The developed set of programs differs from the multi-purpose software of electrodynamic modeling by high speed of preparatory and calculation operations, and the convenience of use.

Link Budget Analysis for Massive-Antenna-Array-Enabled Terahertz Satellite Communications

Broadband satellite communications can enable a plethora of applications in customer services, global nomadic coverage and disaster prediction and recovery. Terahertz (THz) band is envisioned as a key satellite communication technology due to its very broad bandwidth, astrophysical observation advantages and device maturing in recent years. In this paper, a massive-antenna-array-enabled THz satellite communication system is proposed to be established in Tanggula, Tibet, where the average altitude is 5.068 km and the mean-clear-sky precipitable water vapor (PWV) is as low as 1.31 mm. In particular, a link budget analysis (LBA) framework is developed for THz space communications, considering unique THz channel properties and massive antenna array techniques. Moreover, practical siting conditions are taken into account, including the altitude, PWV, THz spectral windows, rain and cloud factors. On the basis of the developed link budget model, the massive antenna array model, and the practical parameters in Tanggula, the performances of signal-to-noise ratio (SNR) and capacity are evaluated. The results illustrate that 1Tbit/s is attainable in the 0.275—0.37 THz spectral window in Tanggula, by using an antenna array of the size 64.

A Novel 3-D Massive MIMO Channel Model for Vehicle-to-Vehicle Communication Environments

This paper presents 3-D vehicle massive multiple-input multiple-output (MIMO) antenna array model for vehicle-to-vehicle (V2V) communication environments. A spherical wavefront is assumed in the proposed model instead of the plane wavefront assumption used in the conventional MIMO channel model. Using the proposed V2V channel model, we first derive the closed-form expressions for the joint and marginal probability density functions of the angle of departure at the transmitter and angle of arrival at the receiver in the azimuth and elevation planes. We additionally analyze the time and frequency cross-correlation functions for different propagation paths. In the proposed model, we derive the expression of the Doppler spectrum due to the relative motion between the mobile transmitter and mobile receiver. The results show that the proposed 3-D channel model is in close agreement with previously reported results, thereby validating the generalization of the proposed model.

Spectral and diffraction properties of microchannel plates in the long-wavelength X-Ray range

The spatial distribution of the intensity and spectra of X rays at the output of microchannel plates is studied both experimentally and theoretically. A model of planar antenna array is used for radiation transmitted through an ordered system of through hollow microchannels for the energy range of 90–2000 eV. The results of the calculations are in good agreement with experimental data obtained with the parallel beams of monochromatic synchrotron radiation. The energy characteristics of the output radiation whose fine spectral structure corresponds to the reflection and fluorescence spectra near the Si L- and Si K-absorption edges are presented.

Systematic approach to sidelobe reduction in linear antenna arrays through corporate‐feed‐controlled excitation

A systematic approach to sidelobe reduction of broadside linear antenna arrays by design of corporate feeds implementing non-uniform excitation is proposed. The approach comprises of the two major stages. First, candidate excitation sets (corporate feeds) are searched among excitation sets which might energize a particular array aperture. The range of the corporate networks is restricted – based on the implementation and performance considerations – to the ones constructed using only T-junctions with equal power split. The reference for the candidates in terms of the sidelobe level is the uniformly excited and spaced array aperture with the same number of elements. The search is performed over realizable excitations and constrained elements’ spacings using the array factor and the model of excitation amplitudes due to corporate feeding. At the second stage, an excitation providing reduced sidelobes and simple routing is implemented as a microstrip corporate feed within the antenna array model. The entire antenna-feed circuit is adjusted and validated using numerical optimization and discrete electromagnetic simulations at the high-fidelity level of description. The proposed feeds and the approach to their systematic design offer flexibility in design of linear antenna arrays without extra complications and allow substantial sidelobe reduction. A demonstration example is provided.

Graphene nanoribbon antenna modeling based on MoM-GEC method for electromagnetic nanocommunications in the terahertz range

In this paper, we present a graphene nanoribbon (GNR)-based terahertz antenna array modeling using the MoM-GEC method (the moments method combined with the generalized equivalent circuit). The quantum mechanical conductivity of graphene is used to introduce the graphene’s effect in the mathematical formulation. The GNR is excited by a gap source with unit voltage localized in its center. The antenna structure is shielded in a rectangular waveguide with electric boundary walls. The proposed formulation is firstly validated and it yields efficient and accurate solutions. The obtained input impedance, current density distribution, and radiated electric field are presented to discuss the antenna performance in cases of single and antennas array. It is demonstrated that all results verify the boundary conditions and behave correctly corresponding to the physical laws. Furthermore, we showed that the antenna array leads to enhance the far-field communications for lower distances compared to conventional antenna.

Parallel FETI‐DP algorithm for efficient simulation of large‐scale EM problems

SummaryAn efficient parallelization of the dual‐primal finite‐element tearing and interconnecting (FETI‐DP) algorithm is presented for large‐scale electromagnetic simulations. As a nonoverlapping domain decomposition method, the FETI‐DP algorithm formulates a global interface problem, whose iterative solution is accelerated with a solution of a global corner problem. To achieve a good load balance for parallel computation, the original computational domain is decomposed into subdomains with similar sizes and shapes. The subdomains are then distributed to processors based on their close proximity to minimize inter‐processor communication. The parallel generalized minimal residual method, enhanced with the iterative classical Gram‐Schmidt orthogonalization scheme to reduce global communication, is adopted to solve the global interface problem with a fast convergence rate. The global corner‐related coarse problem is solved iteratively with a parallel communication‐avoiding biconjugate gradient stabilized method to minimize global communication, and its convergence is accelerated by a diagonal preconditioner constructed from the coarse system matrix. To alleviate neighboring communication overhead, the non‐blocking communication approach is employed in both generalized minimal residual and communication‐avoiding biconjugate gradient stabilized iterative solutions. Three numerical examples are presented to demonstrate the accuracy, scalability, and capability of the proposed parallel FETI‐DP algorithm for electromagnetic modeling of general objects and antenna arrays. Copyright © 2016 John Wiley & Sons, Ltd.

PATTERN SYNTHESIS USING HYBRID FOURIER-NEURAL NETWORKS FOR IEEE 802.11 MIMO APPLICATION

In this paper, the application of Articial Neural Network (ANN) with back-propagation algorithm and weighted Fourier method are used for the synthesis of antenna arrays. The neural networks facilitate the modelling of antenna arrays by estimating the phases. The most important synthesis problem is tond the weights of the linear antenna array elements that are optimum to provide the radiation pattern with maximum reduction in the sidelobe level. This technique is used to prove its effectiveness in improving the performance of the antenna array. To achieve this goal, antenna array for Wi-Fi IEEE 802.11a with frequency at 2 : 4 GHz to 2 : 5 GHz is implemented using Hybrid Fourier-Neural Networks method. To verify the validity of the technique, several illustrative examples of uniform excited array patterns with the main beam are placed in the direction of the useful signal. The neural network synthesis method not only allows to establish important analytical equations for the synthesis of antenna array, but also provides a great exibility between the system parameters in input and output which makes the synthesis possible due to the explicit relation given by them.

Joint use of Bond Graph Approach and Scattering Formalism for an Electrical Modeling of Patch Antenna Array

In this study we present another joint application of the bond graph approach and the scattering formalism for an electrical modeling of a patch antenna array. First, the aim of our application is to build the overall bond graph model of the antenna array using the first principle (physical interpretation to bond graph word of a physical system) of the developed technique by our research team. Second, the simplified model, performed on the found conventional bond graph model gives us easily, on the one hand, the scattering matrix S ij (applying the analytical operating procedure); on the other hand, the electrical model of the patch antenna array. The proposed technique is validated by a comparative study between the simulations of the scattering parameters S ij of the studied structure and the simulations of those founded directly from the electrical model of the antenna. In this study we recall that, the used networks patch antenna has multi-triangular and geometric structures.

Equivalent circuit model of a coaxial excited microstrip‐fed quasi‐lumped element resonator antenna array

An approximate lumped-parameter equivalent circuit model of the quasi-lumped element resonator antenna array is presented. The array consists of six series resonant circuits of frequency-independent elements, each with an interdigital finger capacitor (IDC), and shorted across by a parallel narrow strip inductor. Each resonator exhibits an aperture size of 0.207λg × 0.2λg at a centre frequency of 5.8 GHz, with entire array size of 2.857λg × 1.07λg . The resulting design is fed by a microstrip line and excited by a coaxial feed probe. A simple equivalent circuit model representing the six resonant circuits as well as the coaxial feed probe circuit, using the magnetic-frill model approach but with the simplest uniform-current model is described to predict the characteristics of the proposed resonator (and by extension, the proposed array), the effects of the coaxial probe and the microstrip feed line. Simulated data obtained from a full wave analysis using finite integration technique commercial solver is compared with the Agilent advanced design system results of the equivalent circuit. The derived equivalent circuit model was validated both analytically and by numerical simulations.

Models of optimum radio-systems on the vector combinatorial configurations

Method for construction of optimum radio systems, based on a new conceptual model of the systems - Ideal Ring Vector structures (clusters of the IRV) is proposed. IRV clusters are cyclic ordered sequences of t- integer sub-sequences of the sequence which form perfect relationships of t-dimensional partitions over a virtual t-dimensional lattice covered surface of a finite space interval. The sums of connected sub-sequences of an IRV enumerate the set of tcoordinates specified with respect to cyclic frame reference exactly R-times. This property makes IRVs useful in applications which need to partition multidimensional objects with the smallest possible number of intersections. This sort of models can be used for finding optimal solution for wide classes of technological problems based on the idea of “perfect” vector combinatorial constructions, and expanding the applicability of two-, three- and multidimensional IRV as multidimensional cyclic relationships for fundamental and applied research in systems engineering, for improving such quality indices as vector data coding and signal reconstruction, resolving ability and low side lobe antenna design. There are regarded basic properties these models and made comparative analysis of the models with difference sets. It is shown that the IRVs to be in exceed of difference sets multiply, and set of the classical difference sets is subset of the IRVs. Short review of the methods relating to constructing of the optimum models of non-uniform antenna arrays with respect to low side lobe is given. The problem statement involves development the regular method for construction of the optimum radio-systems using two- and three-dimensional IRVs, and some examples are regarded for illustration its technical merits including algorithm of synthesis of two-dimensional symmetric antenna with 12 elements which provides sufficiently low side lobe radiation levels and shows a flat gain over the frequency range is presented. Method for design of two- or multidimensional vector signals coded based on the optimum binary monolithic code is presented.

Mutual coupling efficient analysis of rectangle microstrip circular polarization antenna array

Mutual coupling performance of the microstrip circular polarization (CP) antenna array is analyzed in this study. Compared with the single antenna application, in the antenna array, the S11, the radiation pattern, and the axial ratio will all be changed due to the mutual coupling and the axial ratio will be more sensitive. To further prove the concept and performance effect, a model of the microstrip antenna array is developed and analyzed in theory. The simulation and measurement results demonstrate that the relative position of antennas in the array exert different effect on the performances of the antenna. Thus, the study provides some very useful results of the CP antenna array.

Conceptual Design of Wireless Anti-Theft Alarm System Based on Antenna Array and Wave Transmission Model

With the development of our society, electronic devices, such as laptops, tablets and mobile phones become increasingly widespread. An accompanying problem of this is the increase of theft aimed at these devices. Even though the proper administration and policy plays an important role to mitigate this crime, they still occur ubiquitously. Therefore, for the sake of eliminating this crime, not only the aspects of administration, policy and legislation should be enhanced, but also the corresponding techniques need to be reinforced. In fact, technology plays a dominant role in preventing crimes. In this paper, a conceptual design of an anti-theft alarm system based on antenna array and wave transmission models will be introduced piece by piece. By implementing a series of electronic components embedded into a protecting wireless network, the location of the protected object can be detected in real time. Once a theft occurs, the computation center will instantaneously obtain the data related to this behavior and assess its authorization and then determine to report or ignore it. This alarm system is specifically suitable for use in public places, for example, libraries, cafes, and holiday villages.