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Academic literature on the topic 'Open waveguides'
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Journal articles on the topic "Open waveguides"
1
Dong, Hao, Jean-Baptiste Doc, and Simon Félix. "Maximum directivity of flanged open-ended waveguides." Journal of the Acoustical Society of America 154, no. 1 (2023): 115–25. http://dx.doi.org/10.1121/10.0020052.
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Directional beams have extensive applications in communication and sound reproduction. This paper investigates the theoretical maximum directivity of infinitely flanged open-ended waveguides and the radiation pattern synthesis. We derive a rigorous solution for the maximum directivity factor of a flanged aperture with arbitrary shape by projecting its surface velocity on the waveguide modes, enabling the creation of a directional beam in any desired direction. We present case studies for a three-dimensional circular waveguide and a bidimensional waveguide. The theoretical beam that is obtained in a subspace spanned by all the propagating modes can then be synthesized by a group of incident modes or a point-source array within the waveguide. The optimality of the beam is demonstrated by comparing it with Gaussian shaded modes radiated from the waveguide. If the evanescent modes are taken into account, the maximum directivity factor increases with considerable loss to the radiation efficiency. Nevertheless, the optimum aperture velocity dominated by its evanescent components is capable of precise beam steering in extreme directions and could be useful for designing material-filled horns. Our work provides benchmark directivity factors and patterns for the practical design of horn antennas. In addition, we present a generalized form of Bouwkamp's impedance theorem.
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Ishibashi, Akira, Tsuyoshi Kasai, and Nobuo Sawamura. "Redirection Waveguide having Discrete Translational Symmetry for Photovoltaic Systems with Solar-Cell Units Placed at the Periphery." Energies 11, no. 12 (2018): 3498. http://dx.doi.org/10.3390/en11123498.
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We have investigated a new type of redirection waveguides for concentration solar-cell systems. The solar cell units are to be placed in the peripheral region of the waveguide. The redirection waveguide converts three-dimensionally propagating (3D) photons into 2D photons that propagate in a planar waveguide which serves as the mainstream of the redirection waveguide. In this new type, the cladding layer on one side of the planar waveguide, not being spatially continuous, tangentially touches the core of the planar waveguide which, having an open geometry, is connected, through tributary waveguides, to the bottom plane where the 3D-photons come in vertically. Based on simulations, we have shown not only that good mainstream-to-mainstream propagation of light-wave can be obtained but also that the light propagation from the tributary waveguides to the mainstream is well done. We also have confirmed that light-waves from the tributary waveguides are well merged with those from the mainstream waveguide at the junction of the cores of the mainstream and the tributary waveguides. Light-waves injected from tributary waveguides propagates well in the core of the mainstream waveguide passing those junctions. The light-wave merging can be fulfilled in the waveguide with the discrete translational symmetry. Photons are shown to be well conveyed in the new waveguide losslessly for a distance of ~1 mm. The redirection waveguide is promising for the concentration photovoltaic systems with solar-cell units placed at its periphery.
3
NICKELSON, L., S. ASMONTAS, V. MALISAUSKAS, and R. MARTAVICIUS. "The dependence of open cylindrical magnetoactive p-Ge and p-Si plasma waveguide mode cutoff frequencies on hole concentrations." Journal of Plasma Physics 75, no. 1 (2009): 35–51. http://dx.doi.org/10.1017/s0022377808007307.
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AbstractIn this article we give the solution of Maxwell's equations for the open circular cylindrical magnetoactive semiconductor plasma (-gyrotropy) waveguides. We describe the method that allowed us to arrive at a dispersion equation for the electrodynamical analyses of open circular cylindrical plasma (OCCP) waveguides. We numerically investigate the main and two higher modes' dispersion characteristics of p-Ge and p-Si waveguides placed in an external constant longitudinal magnetic field at several concentrations of two component hole charge carriers. We analyse the cutoff frequency and other electrodynamical characteristics of helicon modes with the left-handed (e+iϕ) circular polarization. We discover that the cutoff frequencies of the main mode and the working frequency range of OCCP p-Ge and p-Si waveguides are moving continuously towards the direction of higher frequencies when the hole concentration is increasing. We determine that the central frequency of the p-Si plasma waveguide is higher and its broadbandwidth is larger compared with the analogical p-Ge waveguide. We also numerically investigate the helicon mode cutoff frequencies of the infinitive p-Ge and p-Si plasma at several concentrations of two component hole charge carriers. We compare the cutoff frequencies of the helicon modes propagating in the infinite plasma and in the OCCP waveguides.
4
Morozov, V. M., V. I. Magro, and E. Yu Trakhtman. "Infinite linear waveguide antenna array with metal-dielectric structures in the "floquet channel"." Journal of Physics and Electronics 28, no. 1 (2020): 91–96. http://dx.doi.org/10.15421/332015.
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An electrodynamics calculation is performed for an infinite waveguide antenna array in the form of open ends of waveguides, in the near zone of which a metal-dielectric structure is located. This metal-dielectric structure is located in the "Floquet channels" and is a combination of a dielectric coating over the antenna array and horns. In this case, the horns are not a continuation of the waveguides, but are located at some distance from them. The space between the waveguides and the horns is filled with a dielectric. A system of equations that allows calculating the reflection coefficients of incident waves in waveguides is obtained.
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Magro, V. I., and V. M. Morozov. "Study of a finite linear waveguide antenna array with dielectric plugs." Journal of Physics and Electronics 30, no. 2 (2022): 75–80. http://dx.doi.org/10.15421/332223.
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A finite waveguide antenna array of open ends of the waveguides, which are surrounded by a metal screen, is under consideration. The influence of the permittivity and the height of dielectric plugs on the modulus of the reflection coefficient in waveguides of the finite antenna array is studied. Dielectric plugs with different values of permittivity are considered. It is shown that dielectric plugs effectively match the impedance of the antenna array for the case of a slight deviation of the beam from the normal to the array.
6
Polat, Ersin, Henning Tesmer, Roland Reese, et al. "Reconfigurable Millimeter-Wave Components Based on Liquid Crystal Technology for Smart Applications." Crystals 10, no. 5 (2020): 346. http://dx.doi.org/10.3390/cryst10050346.
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This paper presents recent development of tunable microwave liquid crystal (LC) components in the lower millimeter wave (mmW) regime up to the W-band. With the utilization of increasing frequency, conventional metallic waveguide structures prove to be impractical for LC-based components. In particular, the integration of the electric bias network is extremely challenging. Therefore, dielectric waveguides are a promising alternative to conventional waveguides, since electrodes can be easily integrated in the open structure of dielectric waveguides. The numerous subcategories of dielectric waveguides offer a high degree of freedom in designing smart millimeter wave components such as tunable phase shifters, filters and steerable antennas. Recent research resulted in many different realizations, which are analyzed in this paper. The first demonstrators of phased array antennas with integrated LC-based phase shifters are reviewed and compared. In addition, beam steering with a single antenna type is shown. Furthermore, the possibility to realize tunable filters using LC-filled dielectric waveguides is demonstrated.
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Kaddouri, Abdessalem, Bilel Hamdi, Mourad Aidi, and Taoufik Aguili. "GLOBAL METHOD COMBINED WITH FLOQUET MODAL ANALYSIS TO MODEL AN ANTENNA BASED ON RECTANGULAR WAVEGUIDE ARRAY." EPH - International Journal of Science And Engineering 4, no. 2 (2018): 47–55. http://dx.doi.org/10.53555/eijse.v4i2.171.
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In this study, we propose a new formulation based on a global method to model a rectangular waveguide array as antenna. Our method consists to combine the method of moment (MoM), the generalized equivalent circuit method (GECM) and Floquet modal analysis. Looking for rigor, simplicity and rapidity, we repose always on the simple discontinuity in an open rectangular waveguide. So, we extended our pervious works to study in first step an infinite rectangular waveguides array and we achieve with a finite one. For validation purpose, we consider two rectangular waveguides and we compered it whit the same structure studied by direct method in our previous study. Obtained numerical results are presented and discussed. A good agreement is shown and the boundary conditions are verified.
8
Divakov, Dmitriy, Anastasiia Tiutiunnik, and Anton Sevastianov. "Algorithm for Numerical Solution of Diffraction Problem on the Joint of Two Open Three-Layer Waveguides." MATEC Web of Conferences 186 (2018): 01010. http://dx.doi.org/10.1051/matecconf/201818601010.
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This paper describes the algorithm for the numerical solution of the diffraction problem of waveguide modes at the joint of two open planar waveguides. For planar structures under consideration, we can formulate a scalar diffraction problem, which is a boundary value problem for the Helmholtz equation with a variable coefficient in two-dimensional space. The eigenmode problem for an open three-layer waveguide is the Sturm-Liouville problem for a second-order operator with piecewise constant potential on the axis, where the potential is proportional to the refractive index. The described problem is singular and has a mixed spectrum and therefore the Galerkin method can not be used in this definition. One way to adapt the Galerkin method for the problem solution is to artificially limit the area, which is equivalent to placing the open waveguide in question in a hollow closed waveguide whose boundaries are remote from the real boundaries of the waveguide layer of the open waveguide. Thus, we obtain a diffraction problem on a finite interval and with a discrete spectrum, which can be solved by the projection method, as done in this paper.
9
Pochernyaev, V. N., and N. M. Syvkova. "EXTERNAL PARAMETERS OF THE CONNECTION OF A RECTANGULAR WAVEGUIDE PARTIALLY FILLED OF LINEAR DIELECTRIC WITH A RECTANGULAR WAVEGUIDE PARTIALLY FILLED OF NONLINEAR DIELECTRIC." Visnyk Universytetu “Ukraina”, no. 1 (28) 2020 (2020): 100–105. http://dx.doi.org/10.36994/2707-4110-2020-1-28-09.
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. In the article, the external parameters of the connection of a rectangular waveguide partially filled of linear dielectric with a rectangular waveguide partially filled of a nonlinear dielectric are determined. Knowledge of the external parameters of such a connection ensures the design of devices with open nonlinear elements. Promising microwave paths of radio engineering systems based on rectangular waveguides partially filled of dielectric include a wide variety of active and passive microwave devices. The plane-transverse junction of these waveguides is considered for various geometric dimensions of dielectric plates and their relative permittivity. Such a junction is characterized by reactive conductivity, which is determined through the sum of the reactive conductivities of local fields. The transverse electric field at the junction is represented through the eigenvector function of the geometric surface, which coincides with the cross section of the waveguides. The scattering matrix of the plane-transverse junction is determined through the conductivity of the sections of the two waveguides and the conductivity of the plane-transverse junction. The dependences of the traveling wave coefficient and the modulus of the reflection coefficient on the geometric dimensions of the dielectric plate are plotted taking into account the local fields generated at the plane transverse junction. At the junction of two waveguides, not only changed the geometric dimensions of the dielectric plates along the wide and narrow walls of the waveguide, but also their relative permittivity. In one case, two higher types of waves were taken into account: quasi - H30 and quasi - H12, in the other case - four higher types of waves: quasi - H30, quasi - H12, quasi - E12, quasi - H50. Calculations show that an increase in the number of higher types of waves has practically no effect on the accuracy of calculations. The results obtained indicate the rapid internal convergence of the obtained solutions and the correct choice of the transverse electric eigenvector function of rectangular waveguides partially filled of dielectric as approximate the field on the junction of two waveguides.
10
Divakov, Dmitriy, Anastasiia Tiutiunnik, and Anton Sevastianov. "Symbolic-Numeric Computation of the Eigenvalues and Eigenfunctions of the Leaky Modes in a Regular Homogeneous Open Waveguide." MATEC Web of Conferences 186 (2018): 01009. http://dx.doi.org/10.1051/matecconf/201818601009.
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In this paper the algorithm of finding eigenvalues and eigenfunctions for the leaky modes in a three-layer planar dielectric waveguide is considered. The problem on the eigenmodes of open three-layer waveguides is formulated as the Sturm-Liouville problem with the corresponding boundary and asymptotic conditions. In the case of guided and radiation modes of open waveguides, the Sturm-Liouville problem is formulated for self-adjoint second-order operators on the axis and the corresponding eigenvalues are real quantities for dielectric media. The search for eigenvalues and eigenfunctions corresponding to the leaky modes involves a number of difficulties: the boundary conditions for the leaky modes are not self-adjoint, so that the eigenvalues can turn out to be complex quantities. The problem of finding eigenvalues and eigenfunctions will be associated with finding the complex roots of the nonlinear dispersion equation. In the present paper, an original scheme based on the method of finding the minimum of a function of several variables is used to find the eigenvalues. The paper describes the algorithm for searching for eigenvalues, the algorithm uses both symbolic transformations and numerical calculations. On the basis of the developed algorithm, the dispersion relation for the weakly flowing mode of a three-layer open waveguide was calculated in the Maple computer algebra system.