scholarly journals Electromagnetic Insights Into Path Loss Modelling of IRS-Assisted SISO Links: Method-Of-Moment Based Analysis

2021 ◽  
Vol 2 ◽  
Author(s):  
Debdeep Sarkar ◽  
Yahia Antar
Keyword(s):  
Mutual Coupling ◽  
Asymptotic Methods ◽  
Spherical Wave ◽  
Path Loss ◽  
Method Of Moment ◽  
Rectangular Array ◽  
Unit Cells ◽  
Circuit Components ◽  
Loss Modelling ◽  
Speed Accuracy

In this paper, we demonstrate the usefulness of MoM (Method-of-Moments) based methods in efficient path-loss modelling for SISO (single-input single-output) communication links assisted by IRS (Intelligent Reflecting Surfaces). Being a full-wave computational electromagnetic tool, MoM is better equipped compared to high-frequency asymptotic methods like PO (Physical Optics), to handle the crucial electromagnetic (EM) effects like: mutual coupling between IRS unit-cells or interactions with spherical wave-front in antenna near-field. Furthermore, in terms of computational speed, accuracy and reproducibility, the MoM-based MATLAB Antenna Toolbox is significantly advantageous to emulate IRS-assisted wireless channels, as compared to the in-house FDTD (finite-difference time-domain) techniques. We consider a SISO system of two half-wavelength dipoles, and use a rectangular array of circular loops loaded with lumped circuit components as IRS. The lumped circuit loading enables us to control the reactance of individual unit-cells, resulting in alteration of IRS reflection coefficient and consequent changes in channel characteristics. Using numerous numerical simulations, we highlight the impacts of various IRS-parameters like: electrical size and number of unit-cells, distance of IRS from the transmitter/receiver as well as mutual coupling, on the path-loss models (both sub-6 GHz and mm-wave).

scholarly journals Reduction of Mutual Coupling and Return Loss in Microstrip Array Antennas Using Concave Rectangular Patches

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
Shahram Mohanna ◽  
Ali Farahbakhsh ◽  
Saeed Tavakoli ◽  
Nasser Ghassemi
Keyword(s):  
Mutual Coupling ◽  
Return Loss ◽  
Array Antenna ◽  
Effective Solution ◽  
Rectangular Array ◽  
Rectangular Patch ◽  
Array Antennas ◽  
Microstrip Array ◽  
Patch Length ◽  
Microstrip Array Antenna

An effective solution to reduce both the mutual coupling and return loss of a microstrip array antenna consisting of rectangular patches is proposed. The patch is made concave in both horizontal and vertical sides. Applying the proposed structure to a microstrip array antenna having two elements, the effects of patch concavity on the mutual coupling and return loss are simulated and studied. To obtain a concave rectangular patch array antenna having low amounts of mutual coupling and return loss, the patch length and width as well as the amounts of concavities are optimized using an enhanced genetic algorithm. To verify the simulation results, then, the optimal array antenna is fabricated. The simulation and experimental results confirm that the optimal concave rectangular array antenna has low amounts of mutual coupling and return loss.

scholarly journals Design of Non-Uniformly Spaced Circular Arrays of Parasitic Dipoles for Lower Side Lobe Level with Maximum Directivity

2018 ◽  
Vol 7 (1) ◽  
pp. 51-56 ◽  
Author(s):  
H. Patidar ◽  
G. K. Mahanti
Keyword(s):  
Mutual Coupling ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Circular Array ◽  
Method Of Moment ◽  
Lower Side ◽  
New Approach ◽  
Circular Arrays ◽  
Maximum Directivity ◽  
Active Dipole

This paper presents a new approach for circular array of parasitic dipoles composed by one active dipole for reduction of side lobe level with maximum directivity including mutual coupling. The desired goal is obtained by changing the spacing between the parasitic elements and length of the parasitic elements while the position and length of driven element is fixed. In addition to it, reflection coefficient (RC) of the driven element is kept closer to the specified value. Matlab based method of moment code is used to evaluate the performance of circular antenna designs generated by QPSO algorithm. Two examples are presented to show the effectiveness of this proposed approach.  

scholarly journals Fully Metallic Flat Lens Based on Locally Twist-Symmetric Array of Complementary Split-Ring Resonators

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 581 ◽  
Author(s):  
Oskar Dahlberg ◽  
Guido Valerio ◽  
Oscar Quevedo-Teruel
Keyword(s):  
Communication Networks ◽  
Focal Point ◽  
Spherical Wave ◽  
Unit Cell ◽  
Phase Delay ◽  
Ring Resonators ◽  
Wireless Communication Networks ◽  
Split Ring ◽  
Split Ring Resonators ◽  
Unit Cells

In this article, we demonstrate how twist symmetries can be employed in the design of flat lenses. A lens design is proposed, consisting of 13 perforated metallic sheets separated by an air gap. The perforation in the metal is a two-dimensional array of complementary split-ring resonators. In this specific design, the twist symmetry is local, as it is only applied to the unit cell of the array. Moreover, the twist symmetry is an approximation, as it is only applied to part of the unit cell. First, we demonstrate that, by varying the order of twist symmetry, the phase delay experienced by a wave propagating through the array can be accurately controlled. Secondly, a lens is designed by tailoring the unit cells throughout the aperture of the lens in order to obtain the desired phase delay. Simulation and measurement results demonstrate that the lens successfully transforms a spherical wave emanating from the focal point into a plane wave at the opposite side of the lens. The demonstrated concepts find application in future wireless communication networks where fully-metallic directive antennas are desired.

scholarly journals An Anisotropic Auxetic 2D Metamaterial Based on Sliding Microstructural Mechanism

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 429 ◽  
Author(s):  
Teik-Cheng Lim
Keyword(s):  
Poisson’S Ratio ◽  
Nearest Neighbor ◽  
Rapid Change ◽  
Poisson's Ratio ◽  
Rectangular Array ◽  
A Value ◽  
Angular Change ◽  
Unit Cells ◽  
Square Array ◽  
Axes Of Symmetry

A new 2D microstructure is proposed herein in the form of rigid unit cells, each taking the form of a cross with two opposing crossbars forming slots and the other two opposing crossbars forming sliders. The unit cells in the microstructure are arranged in a rectangular array in which the nearest four neighboring cells are rotated by 90° such that a slider in each unit cell is connected to a slot from its nearest neighbor. Using a kinematics approach, the Poisson’s ratio along the axes of symmetry can be obtained, while the off-axis Poisson’s ratio is obtained using Mohr’s circle. In the special case of a square array, the results show that the Poisson’s ratio varies between 0 (for loading parallel to the axes) and −1 (for loading at 45° from the axes). For a rectangular array, the Poisson’s ratio varies from 0 (for loading along the axes) to a value more negative than −1. The obtained results suggest the proposed microstructure is useful for designing materials that permit rapid change in Poisson’s ratio for angular change.

scholarly journals 60 GHz Path Loss Modelling Inside Ships

2020 ◽  
Author(s):  
Brecht De Beelde ◽  
Emmeric Tanghe ◽  
Marwan Yusuf ◽  
David Plets ◽  
Eli De Poorter ◽  
...  
Keyword(s):  
Path Loss ◽  
60 Ghz ◽  
Loss Modelling

scholarly journals Path-loss modelling for WSN deployment in indoor and outdoor environments for medical applications

2018 ◽  
Vol 7 (3) ◽  
pp. 1666 ◽  
Author(s):  
Ahmed Bashar Fakhri ◽  
Sadik Kamel Gharghan ◽  
Saleem Latteef Mohammed
Keyword(s):  
Standard Deviation ◽  
Multipath Propagation ◽  
Path Loss ◽  
Medical Application ◽  
Indoor Environments ◽  
Data Packets ◽  
And Performance ◽  
Log Normal ◽  
Loss Modelling ◽  
Indoor And Outdoor Environments

Wireless sensor networks (WSNs) and their applications have received significantly interested in the last few years. In WSN, knowing an accurate path-loss model as well as packet delivery should be taken into account for the successful distribution of several nodes in the net-work. This paper presents a path-loss modeling and performance evaluation of the ZigBee wireless standard. Received signal strength indi-cator (RSSI) measurements were achieved in outdoor and indoor environments to derive the path-loss based on Log-Normal Shadowing Model (LNSM). The path-loss parameters such as standard deviation and path loss exponents were estimated over point-to-point ZigBee WSN. In addition, the variances of received RSSI values and standard deviation for these values have been investigated. Furthermore, the data packets received is measured practically. Results revealed that the LNSM can be estimated to reflect the channel losses in both outdoor and indoor environments for medical application. The data delivery was achieved successfully of 100% in outdoor which better than indoor due to multipath propagation and shadowing. Moreover, the data packets delivery of the current work outperformed previous work.  

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