Near-Field Focusing in Two-Dimensional Space Enclosed by Arrays of Different Geometries
(2024) EITL01 20241Department of Electrical and Information Technology
- Abstract
- With the increasing demands for higher data rates and long-range wireless power transfer, the development of new methods is a necessary step to meet the heightened requirements. One such method is improving the infrastructure for wireless transmission through the use of large intelligent surfaces (LIS). To be one step closer to enabling the construction of such infrastructure, this study examines the properties of near-field focusing (NFF) in the context of LIS by simulating NFF where the focal point is surrounded by antenna elements. The elements are placed to create two-dimensional (2D) arrays shaped like a circle, triangle, square and rectangle, enclosing a plane where the focal point is placed. The focusing is achieved by using the... (More)
- With the increasing demands for higher data rates and long-range wireless power transfer, the development of new methods is a necessary step to meet the heightened requirements. One such method is improving the infrastructure for wireless transmission through the use of large intelligent surfaces (LIS). To be one step closer to enabling the construction of such infrastructure, this study examines the properties of near-field focusing (NFF) in the context of LIS by simulating NFF where the focal point is surrounded by antenna elements. The elements are placed to create two-dimensional (2D) arrays shaped like a circle, triangle, square and rectangle, enclosing a plane where the focal point is placed. The focusing is achieved by using the conjugate-phase approach. The array's simulated performance is evaluated by considering three performance metrics of NFF, the maximal achieved amplitude of the electric field, the size of the -3 dB spot region and the sidelobe level (SLL).
The results show that depending on where on the enclosed plane the focal point is placed, all performance metrics are affected. When comparing the array configurations, there are differences in regards to how greatly the metrics vary depending on the placement of the focal point. When there are large differences in the distance between the focal point and the closest antenna elements, there are also differences in the studied metrics. It is concluded that it is the inverse proportionality between the amplitude of the electric field and the distance from the focal point to the antenna elements that gives rise to the observed differences. When equalizing the arrays' area, their performance are comparable. All regular geometries with equal area can therefore be considered viable for near-field focusing within the enclosed 2D space.
In general, arrays with smaller area and circumference result in higher maximal electric field amplitude, while the size of the -3 dB region is almost unchanged. The amplitudes of the sidelobes also increase for smaller arrays, but the difference in dBV/m between the maximal amplitude and the highest sidelobe (i.e. SLL) is often similar for all the studied array sizes. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9176920
- author
- Näslund, Doris LU
- supervisor
-
- Jiawang Li LU
- organization
- course
- EITL01 20241
- year
- 2024
- type
- M2 - Bachelor Degree
- subject
- keywords
- Near-field focusing, NFF, Beamforming, Large intelligent surface, LIS, 6G, Antenna array, Phased Array, Conjugate-phase, Radiative near-field
- report number
- LU/LTH-EIT 2024-1026
- language
- English
- id
- 9176920
- date added to LUP
- 2024-10-22 16:16:27
- date last changed
- 2024-10-22 16:16:27
@misc{9176920,
abstract = {{With the increasing demands for higher data rates and long-range wireless power transfer, the development of new methods is a necessary step to meet the heightened requirements. One such method is improving the infrastructure for wireless transmission through the use of large intelligent surfaces (LIS). To be one step closer to enabling the construction of such infrastructure, this study examines the properties of near-field focusing (NFF) in the context of LIS by simulating NFF where the focal point is surrounded by antenna elements. The elements are placed to create two-dimensional (2D) arrays shaped like a circle, triangle, square and rectangle, enclosing a plane where the focal point is placed. The focusing is achieved by using the conjugate-phase approach. The array's simulated performance is evaluated by considering three performance metrics of NFF, the maximal achieved amplitude of the electric field, the size of the -3 dB spot region and the sidelobe level (SLL).
The results show that depending on where on the enclosed plane the focal point is placed, all performance metrics are affected. When comparing the array configurations, there are differences in regards to how greatly the metrics vary depending on the placement of the focal point. When there are large differences in the distance between the focal point and the closest antenna elements, there are also differences in the studied metrics. It is concluded that it is the inverse proportionality between the amplitude of the electric field and the distance from the focal point to the antenna elements that gives rise to the observed differences. When equalizing the arrays' area, their performance are comparable. All regular geometries with equal area can therefore be considered viable for near-field focusing within the enclosed 2D space.
In general, arrays with smaller area and circumference result in higher maximal electric field amplitude, while the size of the -3 dB region is almost unchanged. The amplitudes of the sidelobes also increase for smaller arrays, but the difference in dBV/m between the maximal amplitude and the highest sidelobe (i.e. SLL) is often similar for all the studied array sizes.}},
author = {{Näslund, Doris}},
language = {{eng}},
note = {{Student Paper}},
title = {{Near-Field Focusing in Two-Dimensional Space Enclosed by Arrays of Different Geometries}},
year = {{2024}},
}