Journal ArticleDOI
A Comparison of the Focusing Properties of a Fresnel Zone Plate With a Doubly-Hyperbolic Lens for Application in a Free-Space, Focused-Beam Measurement System
David R. Reid,Glenn S. Smith +1 more
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In this article, a Fresnel zone plate is designed to perform the function of a doubly-hyperbolic lens, and the focusing characteristics of the zone plate and the lens are compared using both measured data and body-of-revolution finite-difference time-domain simulations.Abstract:
A Fresnel zone plate is designed to perform the function of a doubly-hyperbolic lens. The focusing characteristics of the zone plate and the lens are compared using both measured data and body-of-revolution finite-difference time-domain simulations. The results from this comparison are used to evaluate the use of zone plates as focusing elements in a free-space, focused-beam measurement system. A set of two zone plates is used to perform measurements of the material properties of a dielectric sheet, and the results are compared to the results from a standard system which uses two doubly-hyperbolic lenses.read more
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Journal ArticleDOI
Near-Field-Focused Microwave Antennas: Near-field shaping and implementation.
Paolo Nepa,Alice Buffi +1 more
TL;DR: In this paper, the basic working principles and applications of the NF-focused (NFF) microwave antennas as well as the synthesis procedures suggested for the NF shaping around the focal point and the technologies currently used for their implementation are discussed.
Journal ArticleDOI
Focusing Properties of Fresnel Zone Plate Lens Antennas in the Near-Field Region
Shaya Karimkashi,Ahmed A. Kishk +1 more
TL;DR: In this paper, the focusing properties of FZP lens antennas in the near-field region are presented at the ka-band, where they show displacement of the maximum intensity of the electric field along the axial direction from the focal point toward the antenna aperture.
Journal ArticleDOI
Geometrical Optics-Based Model for Dielectric Constant and Loss Tangent Free-Space Measurement
Kamel Haddadi,Tuami Lasri +1 more
TL;DR: A microwave free-space reflection method for determining the complex permittivity of planar dielectric materials is demonstrated that presents a number of features such as low-cost, compactness, robustness, and reliability.
Journal ArticleDOI
Multi-Objective Genetic Algorithm Optimization of Frequency Selective Metasurfaces to Engineer Ku-Passband Filter Responses
TL;DR: This work develops an ultra-wideband frequency selective metasurface (FSmS) that completely encompasses the Ku-band from 12–18 GHz with steep band edges and is optimized by a multi-objective genetic algorithm mimicking evolutionary processes.
Journal ArticleDOI
Technologies for Near-Field Focused Microwave Antennas
TL;DR: In this article, a review of different technologies used to implement near-field focused antennas at the microwave frequency band up to a few tens of GHz is provided, including arrays of microstrip patches and printed dipoles, arrays of dielectric resonator antennas, reflectarrays, transmit antennas, transmit arrays, Fresnel zone plate lenses, leaky-wave antennas and waveguide arrays.
References
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Book
Computational Electrodynamics: The Finite-Difference Time-Domain Method
TL;DR: This paper presents background history of space-grid time-domain techniques for Maxwell's equations scaling to very large problem sizes defense applications dual-use electromagnetics technology, and the proposed three-dimensional Yee algorithm for solving these equations.
Book
Dielectric Materials and Applications
TL;DR: Theory of dielectric measuring techniques and their applications as mentioned in this paper Theoretical and practical applications of die-lectric materials include: insulation strength of high pressure gases and of vacuum liquid dielectrics plastics as dielectors ceramics dielectrices in equipment, capacitors in capacitors rubber and plastics in cables problems of the cable engineer, and the requirements of the armed forces.
Journal ArticleDOI
A free-space method for measurement of dielectric constants and loss tangents at microwave frequencies
TL;DR: In this article, a free-space measurement system was developed for measurements of dielectric properties of planar slabs of ceramic and composite materials, in the frequency range of 14.5-17.5 GHz.
Book
Fresnal Zones in Wireless Links, Zone Plate Lenses and Antennas
TL;DR: In this article, the authors present a comprehensive survey of the application of Fresnel zones in microwave/mm-wave electromagnetics, including the theory, design and practical applications.
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Microstrip Antenna Array With a Beam Focused in the Near-Field Zone for Application in Noncontact Microwave Industrial Inspection
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