Fresnel zone

About: Fresnel zone is a research topic. Over the lifetime, 2337 publications have been published within this topic receiving 37650 citations.

Experimental Research of the Diffraction Pattern of Radiation Reflected from the Retroreflector Spherical Glass Satellite

Abstract: The paper presents experimental research of the diffraction patterns of radiation reflected from the retroreflector spherical system of glass geodesic passive satellites of the Blitz-type created at the JSC "SPC "PSI". The Blitz-type satellites are used in the interests of the GLONASS for high-precision laser ranging and are a set of concentric layers with different refractive indices. The purpose of the study was to determine based on the experiment data the effective beam diameter forming the reflected radiation diffraction pattern in the far zone, which value was required to calculate the satellite energy parameter, i.e., the effective scattering surface. The effective beam diameter dimension for the indicated retroreflector spherical system was determined experimentally by installing various diaphragms that limited the radiation beam size. It is shown that alterations in the diffraction pattern in the far field started, when the diaphragm opening was smaller than the effective diameter. Experimental and calculated values of the satellite’s equivalent scattering surface were comparatively analyzed. According to the experimental results, the diffraction pattern is determined by the central zone of the retroreflector spherical system, where wave aberrations are less than a certain limit corresponding to the Fresnel diffraction with several active first zones

Light focusing by Fresnel phase plates with an inclined zone profile

Abstract: The results of numerical simulation of optical radiation focusing on a mesowavelength Fresnel phase zone plate (ZP) with zones having an inclined profile are presented. In order to reveal the regularities in the formation of the focal spatial structure, the optical field was calculated in the case of diffraction of a monochromatic optical wave by a single ZP. It is shown that the basic parameters of the focal region (intensity, longitudinal and transverse dimensions, focal distance) are sensitive to the angle of inclination of the annular zones of the ZP. By changing the inclination of the edges, it is possible to optimize focusing and achieve its significant enhancement, which, depending on the focal length of the plate, can be up to 40%.

Two cross patterns with the golden mean generated by a square Fibonacci zone plate

Abstract: A square Fibonacci zone plate (SFiZP) is proposed to generate two cross patterns at the positions with the golden mean. Twin vortices with the same topological charge for the spiral-phase SFiZP are found to follow the modulo-4 transmutation rule.

A review of mm-wave and submm-wave antenna and lens developments using Fresnel diffraction theory

Abstract: We present in this paper a review of possible applications of millimeter and sub-millimeter wave Fresnel zone reflectors and lenses those have been performed by working groups at Russia The aim of this paper is to show that this antenna and lenses concept can be a good alternative to improve electrical and mechanical performance of prototypes, reducing design and manufacturing time and cost

New Technique to Design Fresnel Zone Plate Antennas

Abstract: A new method to design Fresnel Zone Plate Antennas (FZPA) is presented in this paper. The proposed method is based on deforming a flat metallic surface in order to achieve the desired phase distribution required to point the main beam to a certain direction. The resulting shaped reflector is modeled by using parametric surfaces, since they allow fitting the real shape of the antenna accurately providing smooth variations. Therefore, the diffraction effect that appears in the transition region between Fresnel zones can be reduced. Unlike bulky parabolic reflectors, FZPAs are much smaller and easy to transport and support, being a promising candidate for satellite communication applications due to its high gain, high polarization purity and minimum volume.