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Fresnel zone
About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.
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Patent•
02 Jul 2020
TL;DR: In this paper, a non-line-of-sight region is extracted by detecting the point cloud data by scanning an area specified by the radius for each position at which the pointcloud data group has been obtained, the ratio of the area of a region constructed by the first Fresnel zone and the area that is the sum of all of the extracted non-linesight regions is calculated, and whether there is a line of sight between the base station device and the terminal station device is determined on the basis of the received power.
Abstract: To reduce the amount of calculation in a millimeter wave wireless communication system.SOLUTION: Point cloud data between a base station device and a terminal station device is acquired to form a point cloud data group, the radius at each position at which the point cloud data group of a first Fresnel zone targeting the base station device and the terminal station device has been obtained is calculated, a non-line-of-sight region is extracted by detecting the point cloud data by scanning an area specified by the radius for each position at which the point cloud data group has been obtained, the ratio of the area of a region constructed by the first Fresnel zone and the area that is the sum of all of the extracted non-line-of-sight regions is calculated, the received power is estimated on the basis of the calculated ratio of the area, and whether there is a line of sight between the base station device and the terminal station device is determined on the basis of the received power.SELECTED DRAWING: Figure 1
TL;DR: In this paper, the authors use the FDTD method to extend the theoretical Fresnel formulation to certain types of problems where Fresnel theory does not apply, such as walls with metallic rebars and similar applications.
Abstract: Analytical expressions for Fresnel reflection and transmission coefficients have been extensively used in ray-tracing simulation. Although these tools accurately predict the field for simple homogeneous wall structures, it is difficult, if not impossible, to extend such an analysis to find reflection and transmission coefficients for walls composed of dielectric and imperfectly conducting materials or complex, inhomogeneous structures. In principle, Fresnel theory is considered a high-frequency method, but in practical problems (such as walls with metallic rebars and similar applications), transmission does not monotonically decrease with incidence angle, and Fresnel theory does not apply. In this paper, we use the FDTD method to extend the theoretical Fresnel formulation to certain types of problems where Fresnel theory does not apply. We find that the presence of rebar affects transmission characteristics much more significantly than permittivity or wall depth. We initially verify the FDTD method with simple theoretical applications, and then we go further in more complicated cases; we furthermore extend our analysis to polarization effects that occur from such inhomogeneities.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Patent•
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18 Jun 1988
TL;DR: In this article, a curved condenser part following a linear condenser is provided to eliminate effect of scattered light caused by the ends of the linear Condenser part. But the curved part does not have the ability to eliminate the effect of the scattered light due to the end of the condenser.
Abstract: PURPOSE:To enable accurate positioning between a mask and a wafer, by providing a curved condenser part following a linear condenser part to eliminate effect of scattered light caused by ends of the linear condenser part. CONSTITUTION:A linear Fresnel zone 1 is set at a specified position of a mask 6 and an alignment light irradiated with linear condenser parts 11 and 12 are condensed to prescribe the mask 6 at a position determined on the wafer 5 irradiating a positioning mark 5a set on the wafer 5. Then, curved condenser parts 3a and 3b are arranged successively on both sides of the parts 11 and 12 to condense the alignment light irradiated to the parts 3a and 3b following both ends of the parts 11 and 12. This eliminates effect of scattered light due to ends of the parts 11 and 12 thereby enabling accurate positioning between the mask 6 and the wafer 5.
TL;DR: In this article, the authors present experimental and theoretical results of X-ray focusing by a grazing incidence phase Fresnel zone plate modulated by a surface acoustic wave, which can simultaneously be focused and deviated by changing the acoustic wavelength.
TL;DR: In this paper , the amplitude of the signal when a person is in the Fresnel zone is compared with the diffraction model to estimate the number of Fresnel zones in which the person is.
Abstract: The information required for location estimation using RF signals is AoA and ToF. In Wi-Fi location estimation, it is possible to obtain AoA by applying MUSIC algorithm, but it is difficult to obtain accurate ToF. In this study, we focused on the Fresnel zone. The amplitude of the signal when a person is in the Fresnel zone is compared with the Fresnel diffraction model to estimate the number of the Fresnel zone in which the person is. By combining the identification of the Fresnel zone with the AoA estimation, we can estimate the location information.