Higher-Order Cylindrical Leaky Waves—Part I: Canonical Sources and Radiation Formulas

Burghignoli, Paolo; Fuscaldo, Walter; Comite, Davide; Baccarelli, Paolo; Galli, Alessandro

doi:10.1109/tap.2019.2922730

Cited by 18 publications

(10 citation statements)

References 42 publications

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“…It is worth to recall here that a simple source, such as a vertical electric dipole (VED), in a partially-open 2-D uniform planar waveguide made of ordinary materials can excite a forward, fast (i.e., 0 < β ρ < k 0 ) cylindrical leaky wave [45,46], thus giving rise to an outward cylindrical aperture distribution (which cannot focus radiation around the axis of symmetry), instead of the required inward one. However, if a radially periodic grating is placed on top of the structure, the period can be selected in order to have the n = −1 Floquet harmonic (note that the radially periodic nature of the grating allows for describing the electromagnetic field in terms of a complete infinite set of Floquet harmonics) radiating with a specific angle at a given frequency.…”

Section: Bessel Beams Leaky-wave Bessel Beams Bessel-gauss Beamsmentioning

confidence: 99%

Bessel-Gauss Beams Through Leaky Waves: Focusing and Diffractive Properties

et al. 2020

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Bessel-Gauss beams have been mainly proposed in optics as a solution for reducing the on-axis intensity oscillations typical of Bessel beams. Previous investigations on Bessel-Gauss beams are based on a scalar theory in the paraxial approximation, and thus cannot be extended to the microwave range where a fully vectorial approach is needed. Here, the generation of Bessel-Gauss beams through leaky waves is investigated. First, the nondiffractive and focusing properties of Bessel-Gauss generated through leaky waves are extensively examined in the frame of a vectorial approach. Useful design criteria are derived to optimize both the radiation and the focusing efficiency of such beams. On this basis, leaky-wave radiators synthesized to support the generation of a Bessel-Gauss beam over a given frequency band in the microwave range are presented. Full-wave results corroborate the concept.

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Section: Bessel Beams Leaky-wave Bessel Beams Bessel-gauss Beamsmentioning

confidence: 99%

Bessel-Gauss Beams Through Leaky Waves: Focusing and Diffractive Properties

et al. 2020

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“…1(b)], the vertical z-component of the magnetic vector potential A has a sin φ variation along the azimuthal plane. Although in principle, cylindrical waves with higher order φ variation could be treated (see, e.g., [36], [37], [38]), the n = 0 (for the cases with azimuthal symmetry) and n = 1 modes are the most important since elementary electric and magnetic dipoles within layered media will excite only these wave types [35]. An HMD excites both TE and TM waves that can initially be studied separately and then added together.…”

Section: Theoretical Approachmentioning

confidence: 99%

Leaky-Wave Analysis of TM-, TE-, and Hybrid-Polarized Aperture-Fed Bessel-Beam Launchers for Wireless-Power-Transfer Links

Negri

Fuscaldo

Burghignoli

et al. 2023

IEEE Trans. Antennas Propagat.

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Bessel beams (BBs) can be generated at microwave frequencies by means of compact, planar devices based on Fabry-Perot cavity leaky-wave resonators. Most designs are based on the excitation of a single transverse magnetic/transverse electric (TM/TE) leaky mode by means of a vertical electric/magnetic dipole source. In this work, we analyze the important case of a horizontal magnetic dipole, which excites both TM and TE modes, developing an original theoretical framework suitable for resonant radiators. Analytical expressions are provided for the dominant leaky-wave aperture field. The near-field distribution is then evaluated through an accurate numerical integration of the radiating currents and validated through full-wave simulations for the relevant case of a BB launcher when excited by a waveguide-fed slot. Different designs are presented and analyzed in order to obtain TM, TE, and hybrid polarizations, finding in all cases an excellent agreement between simulations and theoretical results. Finally, we evaluate and compare the wireless-power-transfer efficiency of two coupled TM-, TE-, or hybrid-polarized BB launchers when a wireless link is established in the radiative near-field region. Interestingly, full-wave results demonstrate the superior performance of resonant BB launchers in TM or TE polarization with respect to the nonresonant hybrid case.

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“…In a 2D-LWA excited by a finite three-dimensional (3D) source, the field distribution is mainly described by cylindrical leaky waves that propagate in the transverse plane with a complex radial wavenumber k ρ = β ρ − jα ρ , where β ρ and α ρ are the phase and the leakage constant, respectively [25]. It is worthwhile recalling here that β ρ is intimately related to the axicon angle θ 0 (which entirely defines the focusing properties of Bessel beams [21]) through the well-known ray-optics formula β ρ /k 0 = sin θ 0 [26].…”

Section: The Leaky-wave Approachmentioning

confidence: 99%

A Leaky-Wave Analysis of Resonant Bessel-Beam Launchers: Design Criteria, Practical Examples, and Potential Applicationsat Microwave and Millimeter-Wave Frequencies

et al. 2022

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Resonant Bessel-beam launchers are low-cost, planar, miniaturized devices capable of focusing electromagnetic radiation in a very efficient way in various frequency ranges, with recent increasing interest for microwave and millimeter-wave applications (i.e., 3–300 GHz). In recent years, various kinds of launchers have appeared, with different feeding mechanisms (e.g., coaxial probes, resonant slots, or loop antennas), field polarization (radial, azimuthal, and longitudinal), and manufacturing technology (axicon lenses, radial waveguides, or diffraction gratings). In this paper, we review the various features of these launchers both from a general electromagnetic background and a more specific leaky-wave interpretation. The latter allows for deriving a useful set of design rules that we here show to be applicable to any type of launcher, regardless its specific realization. Practical examples are discussed, showing a typical application of the proposed design workflow, along with a possible use of the launchers in a modern context, such as that of wireless power transfer at 90 GHz.

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Higher-Order Cylindrical Leaky Waves—Part I: Canonical Sources and Radiation Formulas

Cited by 18 publications

References 42 publications

Bessel-Gauss Beams Through Leaky Waves: Focusing and Diffractive Properties

Bessel-Gauss Beams Through Leaky Waves: Focusing and Diffractive Properties

Leaky-Wave Analysis of TM-, TE-, and Hybrid-Polarized Aperture-Fed Bessel-Beam Launchers for Wireless-Power-Transfer Links

A Leaky-Wave Analysis of Resonant Bessel-Beam Launchers: Design Criteria, Practical Examples, and Potential Applicationsat Microwave and Millimeter-Wave Frequencies

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