Effects of dielectric covers over cross slots in a rectangular waveguide
Dielectric cover effects on radiation properties of cross slots in rectangular antenna
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Results for “dielectric waveguide”
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The impedance properties of dielectric-covered narrow radiating slots in the broad face of a rectangular waveguide
Dielectric covered narrow radiating slots in rectangular waveguide broad face, calculating impedance from equivalent circuits
Bailey, M. C.↗
Measurement and analysis of periodic coupling in silicon-clad planar waveguides
Computer modeling studies indicate that planar dielectric waveguides clad with silicon exhibit a damped periodic oscillation in their attenuation and phase characteristics. The effect is due to a periodic coupling between the lossy, guided modes in the silicon film and the TE0 mode of the dielectric waveguide. Experimental confirmation of the periodic coupling for a wavelength of 632.8 nm is presented. Propagation characteristics for a wavelength of 1150 nm were investigated for application in integrated optical modulators. Frequency filtering properties of silicon-clad waveguides are also examined and it is shown that the silicon thickness controls the filter response curve.
Mcwright, G. M.↗
Waveguide excited dielectric spheres as feeds.
The results of experiments with dielectric obstacles of various geometries placed directly upon the apertures of circular and rectangular waveguides are presented. It is found that dielectric spheres, and in some instances dielectric cubes, two to four wavelengths in dimension produce directive patterns with low sidelobe levels. For some cross sections, the measured gain of these antennas is greater (6 dB in some cases) than that produced by optimum horns having apertures of identical cross section. The linearity of the polarization of these antennas is essentially the same as that of an open-end waveguide antenna.
Chatterjee, J. S.↗
Waveguide laser mode patterns in the near and far field.
The difference in notations used by researchers in the dielectric waveguide field and those primarily interested in waveguide lasers is discussed, and the equations for the field components of the various modes in large radius hollow dielectric waveguides are rederived in terms of the more widely used notation. Certain linear combinations of these modes that give linearly polarized field distributions are then considered to be launched into free-space at a waveguide termination. The resultant Fresnel and Fraunhofer field distributions are useful in identifying the modes of oscillation and in choosing mirror apertures that will restrict oscillation on the fundamental waveguide mode.
Degnan, J. J.↗
Control of wakefield in sub-THz dielectric-lined waveguides using multiple-bunch excitation
Beam-driven wakefield accelerators offer the potential to achieve accelerating fields approaching the sub-GV/m range, paving the way for compact and cost-effective next-generation high-energy colliders. This method typically employs a two-bunch system: a drive bunch that excites an electromagnetic wakefield in a solid-state or plasma medium, and a witness bunch that extracts energy from the wake for acceleration. Our research focuses on two key challenges in wakefield acceleration using structures. First, we investigate strategies to suppress transverse instabilities by employing non-cylindrical geometries that damp dipole modes. Second, we explore methods to precisely terminate the wakefield after the interaction region, thereby improving the efficiency of energy transfer. This paper presents detailed simulation results and the corresponding experimental design developed to validate these concepts. Furthermore, the proposed experiment will be carried out at the Argonne Wakefield Accelerator (AWA) facility, focusing on controlling wakefield duration through tailored drive and witness bunch configurations and evaluating dielectric-lined structures with non-cylindrical cross sections.
43 PARTICLE ACCELERATORS↗
Phased array antenna matching: Simulation and optimization of a planar phased array of circular waveguide elements
A computerized simulation of a planar phased array of circular waveguide elements is reported using mutual coupling and wide angle impedance matching in phased arrays. Special emphasis is given to circular polarization. The aforementioned computer program has as variable inputs: frequency, polarization, grid geometry, element size, dielectric waveguide fill, dielectric plugs in the waveguide for impedance matching, and dielectric sheets covering the array surface for the purpose of wide angle impedance matching. Parameter combinations are found which produce reflection peaks interior to grating lobes, while dielectric cover sheets are successfully employed to extend the usable scan range of a phased array. The most exciting results came from the application of computer aided optimization techniques to the design of this type of array.
Dudgeon, J. E.↗
Polarization effects in silicon-clad optical waveguides
By changing the thickness of a semiconductor cladding layer deposited on a planar dielectric waveguide, the TE or TM propagating modes may be selectively attenuated. This polarization effect is due to the periodic coupling between the lossless propagating modes of the dielectric slab waveguide and the lossy modes of the cladding layer. Experimental tests involving silicon claddings show high selectivity for either polarization.
Carson, R. F.↗
Synthesis of Novel All-Dielectric Grating Filters using Genetic Algorithms
The feasibility of novel all-dielectric waveguide grating filters is demonstrated, using a genetic algorithm to solve for material dielectric constants and geometric boundaries separating homogeneous regions of the periodic cell.
all-dielectric↗
Thin Ribbon Tapered Coupler for Dielectric Waveguide/Optical Fiber
This paper presents a new way to design a low-loss couipler for high- or low-dielectric constant, dielectric waveguide for optical or millimeter/submillimeter waves.
coupler dielectric waveguide↗
Admittance of a waveguide-fed aperture loaded with a dielectric plug.
Waveguide fed rectangular aperture antenna with dielectric plug load, describing admittance resonant perturbation due to excited TE mode
Swift, C. T.↗
High-frequency feed structure antenna apparatus and method of use
An antenna apparatus for the reception of, and or transmission of, electromagnetic energy, the apparatus including a non-radiating dielectric waveguide aperture coupled to at least one dielectric rod antenna, which is electromagnetically coupled to a transmission line element.
Sarehraz, Mohammad↗
Optimizing structured surfaces for diffractive waveguides
We introduce universal diffractive waveguide designs that can match the performance of conventional dielectric waveguides and achieve various functionalities. Optimized using deep learning, diffractive waveguides can be cascaded to form any desired length and are comprised of transmissive diffractive surfaces that permit the propagation of desired modes with low loss and high mode purity. In addition to guiding the targeted modes through cascaded diffractive units, we also developed various waveguide components and introduced bent diffractive waveguides, rotating the direction of mode propagation, as well as spatial and spectral mode filtering and mode splitting diffractive waveguide designs, and mode-specific polarization control. This framework was experimentally validated in the terahertz spectrum to selectively pass certain spatial modes while rejecting others. Without the need for material dispersion engineering diffractive waveguides can be scaled to operate at different wavelengths, including visible and infrared spectrum, covering potential applications in, e.g., telecommunications, imaging, sensing and spectroscopy.
Applied optics↗
A single-mode waveguide laser.
Laser with neodymium doped glass slab forming core region of single mode optical dielectric waveguide
Flam, R. P.↗
Electromagnetic wave energy conversion research
Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.
Bailey, R. L.↗
Method of manufacturing a waveguide comprising stacking dielectric layers having aligned metallized channels formed therein to form the waveguide
Waveguides and methods for manufacturing a waveguide that include forming a first channel in a first layer of dielectric material, the first channel comprising one or more walls; forming a second channel in a second layer of dielectric material, the second channel comprising one or more walls; depositing electrically conductive material on the one or more walls of the first channel; depositing electrically conductive material on the one or more walls of the second channel; arranging the first layer adjacent to the second layer to form a stack with the first channel axially aligned with and facing the second channel; and heating the stack so that the conductive material on the one or more walls of the first channel and the conductive material on the one or more walls of the second channel connect to form the waveguide.
Krueger, Daniel Scott↗
Designing Dielectric Grating Filters with PGAPACK
The chapter is concerned with the design of planar dielectric layer diffraction gratings, which exhibit sharp resonances due to the coupling of exterior evanescent diffractive fields to the leaky modes of dielectric waveguides.
genetic algorithms↗
Alumina or Semiconductor Ribbon Waveguides at 30 to 1,000 GHz
Ribbon waveguides made of alumina or of semiconductors (Si, InP, or GaAs) have been proposed as low-loss transmission lines for coupling electronic components and circuits that operate at frequencies from 30 to 1,000 GHz. In addition to low losses (and a concomitant ability to withstand power levels higher than would otherwise be possible), the proposed ribbon waveguides would offer the advantage of compatibility with the materials and structures now commonly incorporated into integrated circuits. Heretofore, low-loss transmission lines for this frequency range have been unknown, making it necessary to resort to designs that, variously, place circuits and components to be coupled in proximity of each other and/or provide for coupling via free space through bulky and often lossy optical elements. Even chip-to-chip interconnections have been problematic in this frequency range. Metal wave-guiding structures (e.g., microstriplines and traditional waveguides) are not suitable for this frequency range because the skin depths of electromagnetic waves in this frequency range are so small as to give rise to high losses. Conventional rod-type dielectric waveguide structures are also not suitable for this frequency range because dielectric materials, including ones that exhibit ultralow losses at lower frequencies, exhibit significant losses in this frequency range. Unlike microstripline structures or metallic waveguides, the proposed ribbon waveguides would be free of metal and would therefore not be subject to skin-depth losses. Moreover, although they would be made of materials that are moderately lossy in the frequency range of interest, the proposed ribbon waveguides would cause the propagating electromagnetic waves to configure themselves in a manner that minimizes losses.
Yeh, Cavour↗