scholarly journals Optimal Design of Switchable Wearable Antenna Array for Wireless Sensor Networks

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2795
Author(s):  
Łukasz Januszkiewicz ◽  
Paolo Di Barba ◽  
Sławomir Hausman
Keyword(s):  
Radiation Pattern ◽  
Antenna Arrays ◽  
Optimized Design ◽  
Computationally Efficient ◽  
Wearable Antenna ◽  
Novel Approach ◽  
Nadir Point ◽  
Distance Minimization ◽  
Element Array ◽  
Point Distance

In the paper, we present a novel approach to the optimum design of wearable antenna arrays intended for off-body links of wireless body area networks. Specifically, we investigate a four-element array that has a switchable radiation pattern able to direct its higher gain towards a signal source and a lower gain towards an interference. The aim is to increase the signal to interference ratio. We apply a genetic algorithm to optimize both the spatial placement and the feed phasing of the elementary on-body antennas. We propose a simplified, computationally efficient model for the simulation of the array radiation pattern. The model is based on full-wave simulations obtained with a simplified cylindrical model of the human body. We also propose, implement, and evaluate four objective functions based on signal to interference ratio, i.e., min-max, nadir point distance maximization, utopia point distance minimization, and full Pareto-like. Our optimized design obtained with this approach exhibits a significant performance improvement in comparison to the initial heuristic design.

scholarly journals Principles of adaptive element spacing in linear array antennas

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tanzeela Mitha ◽  
Maria Pour
Keyword(s):  
Antenna Arrays ◽  
Communication Systems ◽  
Linear Array ◽  
Main Idea ◽  
Phase Center ◽  
Array Configuration ◽  
Array Antennas ◽  
Center Location ◽  
Novel Approach ◽  
Array Performance

AbstractA novel approach to linear array antennas with adaptive inter-element spacing is presented for the first time. The main idea is based upon electronically displacing the phase center location of the antenna elements, which determine their relative coordinates in the array configuration. This is realized by employing dual-mode microstrip patch antennas as a constitutive element, whose phase center location can be displaced from its physical center by simultaneously exciting two modes. The direction and the amount of displacement is controlled by the amplitude and phase of the modes at the element level. This in turn facilitates reconfiguring the inter-element spacing at the array level. For instance, a uniformly-spaced array could be electronically transformed into a non-uniform one without any mechanical means. The proposed idea is demonstrated in two- and three-element linear antenna arrays. The technique has the potential to control the radiation characteristics such as sidelobe levels, position of the nulls, and the beamwidths in small arrays, which are useful for adaptively controlling the array performance in emerging wireless communication systems and radars.

scholarly journals Modified Dual-Band Stacked Circularly Polarized Microstrip Antenna

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Guo Liu ◽  
Liang Xu ◽  
Yi Wang
Keyword(s):  
Radiation Pattern ◽  
Global Positioning System ◽  
Microstrip Antenna ◽  
High Performance ◽  
Axial Ratio ◽  
Dual Band ◽  
Optimized Design ◽  
Positioning System ◽  
Circularly Polarized ◽  
Global Positioning

A novel high-performance circularly polarized (CP) antenna is proposed in this paper. Two separate antennas featuring the global positioning system (GPS) dual-band operation (1.575 GHz and 1.227 GHz for L1 band and L2 band, resp.) are integrated with good isolation. To enhance the gain at low angle, a new structure of patch and two parasitic metal elements are introduced. With the optimized design, good axial ratio and near-hemispherical radiation pattern are obtained.

A Comparison of Swarm-Based Optimization Algorithms in Linear Antenna Array Synthesis

2021 ◽  
Author(s):  
Ali Durmus ◽  
Rifat KURBAN ◽  
Ercan KARAKOSE
Keyword(s):  
Antenna Array ◽  
Radiation Pattern ◽  
Antenna Arrays ◽  
Heuristic Algorithms ◽  
Beam Width ◽  
Side Lobe ◽  
Side Lobe Level ◽  
Linear Antenna ◽  
Half Power ◽  
Antenna Array Synthesis

Abstract Today, the design of antenna arrays is very important in providing effective and efficient wireless communication. The purpose of antenna array synthesis is to obtain a radiation pattern with low side lobe level (SLL) at a desired half power beam width (HPBW) in far-field. The amplitude and position values ​​of the array elements can be optimized to obtain a radiation pattern with suppressed SLLs. In this paper swarm-based meta-heuristic algorithms such as Particle Swarm Optimization (PSO), Artificial Bee Colony (ABC), Mayfly algorithm (MA) and Jellyfish Search (JS) algorithms are compared to realize optimal design of linear antenna arrays. Extensive experiments are conducted on designing 10, 16, 24 and 32-element linear arrays by determining the amplitude and positions. Experiments are repeated 30 times due to the random nature of swarm-based optimizers and statistical results show that performance of the novel algorithms, MA and JS, are better than well-known methods PSO and ABC.

Damage Identification in Collocated Structural Systems Using Structural Markov Parameters

2013 ◽  
Author(s):  
Ramin Bighamian ◽  
Hamid Reza Mirdamadi ◽  
Jin-Oh Hahn
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Mode Shapes ◽  
Structural Systems ◽  
Structural System ◽  
Computationally Efficient ◽  
Markov Parameters ◽  
Novel Approach ◽  
Stiffness Matrices ◽  
Stiffness Characteristics

This paper presents a novel approach to damage identification in a class of collocated multi-input multi-output structural systems. In the proposed approach, damage is identified via the structural Markov parameters obtained from a system identification procedure, which is in turn exploited to localize and quantify damage by evaluating relative changes occurring in the mass and stiffness matrices associated with the structural system. To this aim, an explicit relationship between structural Markov parameters versus mass and stiffness matrices is developed. The main strengths of the proposed approach are that it is capable of quantitatively identifying the occurrence of multiple damages associated with both mass and stiffness characteristics in the structural system, and it is computationally efficient in that it is solely based on the structural Markov parameters but does not necessitate costly calculations related to natural frequencies and mode shapes, making it highly attractive for structural damage detection and health monitoring applications. Numerical examples are provided to demonstrate the validity and effectiveness of the proposed approach.

scholarly journals Wideband Omnidirectional Slotted-Waveguide Antenna Array Based on Trapezoidal Slots

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Hugo Rodrigues Dias Filgueiras ◽  
James R. Kelly ◽  
Pei Xiao ◽  
I. F. da Costa ◽  
Arismar Cerqueira Sodré
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Longitudinal Axis ◽  
Fractional Bandwidth ◽  
Slot Length ◽  
Novel Approach ◽  
Gain Variation ◽  
Operating Bandwidth ◽  
Slotted Waveguide ◽  
24 Ghz

This manuscript presents a novel approach for designing wideband omnidirectional slotted-waveguide antenna arrays, which is based on trapezoidal-shaped slots with two different electrical lengths, as well as a twisted distribution of slot groups along the array longitudinal axis. The trapezoidal section is formed by gradually increasing the slot length between the waveguide interior and exterior surfaces. In this way, a smoother impedance transition between waveguide and air is provided in order to enhance the array operating bandwidth. In addition, we propose a twisting technique, responsible to improve the omnidirectional pattern, by means of reducing the gain ripple in the azimuth plane. Experimental results demonstrate 1.09 GHz bandwidth centered at 24 GHz (4.54% fractional bandwidth), gain up to 14.71 dBi over the operating bandwidth, and only 2.7 dB gain variation in the azimuth plane. The proposed antenna array and its enabling techniques present themselves as promising solutions for mm-wave application, including 5G enhanced mobile broadband (eMBB) communications.

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