Concept for equivalent dielectric constant of planar transmission lines on anisotropic substrates
01 Oct 2016-pp 158-161
TL;DR: The concept and procedure for determination of the equivalent dielectric constant of different planar transmission lines on anisotropic substrates have been considered in this paper, where the obtained results have been presented for several planar lines with different ratio between the parallel and perpendicular electric fields.
Abstract: The concept and procedure for determination of the equivalent dielectric constant of different planar transmission lines on anisotropic substrates have been considered in this paper. The obtained results have been presented for several planar lines with different ratio between the parallel and perpendicular electric fields. Finally, a preliminary discussion has been given for the efficiency of the 3-D numerical design by replacement of different simple planar structures on anisotropic substrate with their planar isotropic equivalents.
Citations
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01 Sep 2017
TL;DR: In this paper, a set of numerical and experimental investigations of the resulting uniaxial anisotropy of the modern artificial dielectrics with antenna applications is performed. But the results are limited to 3-D printed Luneburg lens antennas, fabricated by applying of unit cells with different symmetry.
Abstract: In this paper we perform a set of numerical and experimental investigations of the resulting uniaxial anisotropy of the modern artificial dielectrics with antenna applications — reinforced substrates, 3-D printed and multilayer structures, textile fabrics, some metamaterials, etc. They all usually are mixtures between two or more dielectrics or metals and we estimate their anisotropy using inclusions with different shapes (spheres, cubes, cylinders, disks, etc.) and different dielectric parameters. Experimental data are presented for isotropic polycarbonate sheets with air holes or with surface metal inclusions, for dielectric nets and textile fabrics. Special attention is devoted for determination of the resulting anisotropy in 3-D printed Luneburg lens antennas, fabricated by applying of unit cells with different symmetry.
13 citations
TL;DR: A complete analysis of the complex dielectric constant of a flexible substrate from the silicon-based polymer- Polydimethylsiloxane (PDMS) is performed, and the obtained results show that PDMS substrates have relatively weak but measurable uniaxial anisotropy and well-expressed frequency dependencies of the extracted dielectrics parameters.
Abstract: In this paper, a complete analysis of the complex dielectric constant of a flexible substrate from the silicon-based polymer- Polydimethylsiloxane (PDMS) is performed, and the obtained results are discussed. Two experimental methods are applied in this research. The first Two-resonator method is based on resonance measurements by excitation of two types of TE- and TM-mode cylinder resonators with PDMS disks, ensure an accurate determination of the dielectric constant and dielectric loss tangent in both parallel and perpendicular directions (e.g., $\varepsilon _{\textit {par}}$ and $\varepsilon _{\textit {perp}}$ ). The second method is based on the tight coverage of planar microstrip ring resonators with non- metalized PDMS samples gives reliable information for the equivalent dielectric parameters (e.g., $\varepsilon _{\textit {eq}}$ , tan $\delta _{\varepsilon \textit {eq}}$ ). The obtained results show that PDMS substrates have relatively weak but measurable uniaxial anisotropy and well-expressed frequency dependencies of the extracted dielectric parameters in the range 1–40 GHz, namely $\varepsilon _{\textit {par}} \sim 2.82$ -2.7; $\varepsilon _{\textit {perp}} \sim 2.73$ -2.52 and $\varepsilon _{\textit {eq}} \sim 2.75$ -2.64, tan $\delta _{\varepsilon eq} \sim 0.017$ -0.048. The results are confirmed by several other complementary methods. The considered pair of methods are also applied in the temperature interval–40/ $+ 70^{\circ }\text{C}$ ; the measured temperature dependencies on the dielectric parameters turn out to be relatively strong. The possible origin of the measured PDMS uniaxial anisotropy has been discussed; in fact, it appears mainly in the temperature range–30/ $+ 40^{\circ }\text{C}$ .
10 citations
01 Mar 2017
TL;DR: In this article, the authors investigated the possibilities for direct measurements of the equivalent dielectric constants for microstrip lines and coplanar waveguides by covering with thick enough overlays from the same material, and proposed a direct method for determination of a set of three equivalent parameters of microwave substrates.
Abstract: The paper considers the problems of the dielectric anisotropy and determination of so-called equivalent dielectric constant of different planar transmission lines on anisotropic substrates, when they have been covered with dielectric overlays with open or shielded top surfaces. The idea is to investigate the possibilities for direct measurements of the equivalent dielectric constants for microstrip lines and coplanar waveguides by covering with thick enough dielectric overlays from the same material. A direct method has been proposed for determination of a set of three equivalent parameters of microwave substrates, applicable for more accurate 3D design of MW planar structures.
5 citations
Cites background from "Concept for equivalent dielectric c..."
...The results in [7] actually shown that the equivalent dielectric constant εeq_Line of each planar line on anisotropic substrate naturally depends on the balance between the parallel and perpendicular electric fields of the dominant mode in the crosssection of the selected structure....
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...(from [7]) Averaged by thickness and frequency equivalent dielectric constant values of six planar lines for two typical substrates with specification Dk 3....
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...We already discussed in the conference paper [7] our ideas how to solve the problems of dielectric anisotropy in order to support the modern 3D numerical design by adequate ways as for the substrate users (microwave designers), as well as for the substrate vendors....
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...The problem is that the “design” value depends on the type of the planar transmission line as it is shown in [7], which complicates the application of the equivalent parameters’ approach....
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01 Feb 2020
TL;DR: Measurements of flat/bent microstrip patch radiators on selected isotropic/anisotropic textile substrates have been performed and results show that both parameters have concurrent influences on the resonance behavior of structures.
Abstract: In this paper, we consider the simultaneous influence of dielectric anisotropy of textile fabrics used for wearable antennas and their bending. Measurements of flat/bent microstrip patch radiators on selected isotropic/anisotropic textile substrates have been performed, and results have been compared with simulations. They show that both parameters have concurrent influences on the resonance behavior of structures.
2 citations
Cites background from "Concept for equivalent dielectric c..."
...The resonance frequencies of the planar flat resonators depend mainly on the ratio between the perpendicular and parallel values of the substrate dielectric constant [17]; in other words, on the so-called “equivalent dielectric constant” of the substrate in MSL geometry [18]....
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References
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Book•
01 Jun 1979
TL;DR: In this article, the authors present a quasi-static analysis of an Enclosed Microstrip and a Slot-Coupled Microstrip Line, as well as a fullwave analysis of Discontinuity Inductance Evaluation.
Abstract: Microstrip Lines I: Quasi-Static Analyses, Dispersion Models, and Measurements -Introduction. Quasi-Static Analyses of a Microstrip. Microstrip Dispersion Models. Microstrip Transitions. Microstrip Measurements. Fabrication. Microstrip Lines II: Fullwave Analyses, Design Considerations, and Applications - Methods of Fullwave Analysis. Analysis of an Open Microstrip. Analysis of an Enclosed Microstrip. Design Considerations. Other Types of Microstrip Lines. Microstrip Applications. Microstrip Discontinuities I: Quasi-Static Analysis and Characterization -Introduction. Discontinuity Capacitance Evaluation. Discontinuity Inductance Evaluation. Characterization of Various Discontinuities. Compensated Microstrip Discontinuities. Microstrip Discontinuities II: Fullwave Analysis and Measurements - Planar Waveguide Analysis. Fullwave Analysis of Discontinuities. Discontinuity Measurements. Slotlines -Introduction. Slotline Analysis. Design Considerations. Slotline Discontinuities. Variants of Slotline. Slotline Transitions. Slotline Applications. Defected Ground Structure (DGS) -Introduction. DGS Characteristics. Modeling of DGS. Applications of DGS. Coplanar Lines: Coplanar Waveguide and Coplanar Strips -Introduction. Analysis. Design Considerations. Losses in Coplanar Lines. Effect of Tolerances. Comparison with Microstrip Line and Slotline. Transitions. Discontinuities in Coplanar Lines. Coplanar Line Circuits. Coupled Microstrip Lines -Introduction. General Analysis of Coupled Lines. Characteristics of Coupled Microstrip Lines. Measurements on Coupled Microstrip Lines. Design Considerations for Coupled Microstrip Lines. Slot-Coupled Microstrip Lines. Coupled Multiconductor Microstrip Lines. Discontinuities in Coupled Microstrip Lines. Substrate Integrated Waveguide (SIW) -Introduction. Analysis Techniques of SIW. Design Considerations. Other SIW Configurations. Transitions Between SIW and Planar Transmission Lines. SIW Components and Antennas. Fabrication Technologies and Materials.
2,182 citations
"Concept for equivalent dielectric c..." refers methods in this paper
...for εeff_MSL and family of calculated dependencies, obtained by three methods: TRL calculators, 3-D simulations and published CAD models [12, 13] a)...
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...We can apply three the most applicable methods in the RF design – closed-form analytical CAD expressions (where they exist; see [12-13]); popular transmission-line (TRL) impedance calculators and accurate numerical simulations of well-constructed 3-D models of each planar line by commercial 3-D simulators....
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Book•
16 Apr 2004
TL;DR: In this article, the authors present a method for measuring the dieletric properties of materials at high temperatures, including the properties of Ferroelectric materials and their properties in terms of permittivity and permutation.
Abstract: Preface.1. Electromagnetic Properties of Materials.2. Microwave Theory and Techniques for Materials Characterization.3. Reflection Methods.4. Transmission/Reflection Methods.5. Resonator Methods.6. Resonant-perturbation Methods.7. Planar-circuit Methods.8. Measurements of Permittivity and Permeability Tensors.9. Measurement of Ferroelectric Materials.10. Microwave Measurement of Chiral Materials.11. Measurement of Microwave Electrical Transport Properties.12. Measurement of Dieletric Properties of Materials at High Temperatures.Index.
1,077 citations
"Concept for equivalent dielectric c..." refers methods in this paper
...Two of the measurement methods are most popular [11]: the differential phase length method (see Fig....
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...The procedure for measurement of the effective dielectric constant εeff_MSL of microstrip lines is well established [11]....
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Book•
31 May 1991
TL;DR: In this paper, the authors present a comprehensive overview of transmission line components and discontinuities, including coupled lines, capacitors, and resistors, as well as a glossary of special functions.
Abstract: Generalized Transmission Lines. Physical Transmission Lines. Coupled Lines. Transmission Line Components and Discontinuities. Inductors. Capacitors. Resistors. Printed Circuit Fabrication. Cable Dielectrics. Wire Gauges. Special Functions. Glossary. Appendices.
880 citations
TL;DR: In this paper, a two-resonator method based on TE/sub 011/-mode and TM/sub 0/-mode resonance cavities with a multilayer disk sample was developed for measurements of the longitudinal and transversal dielectric constant and the loss tangent of each layer or in the whole sample averaging over the layers contribution.
Abstract: A two-resonator method, based on TE/sub 011/-mode and TM/sub 010/-mode resonance cavities with a multilayer disk sample, has been developed for measurements of the longitudinal and transversal dielectric constant and dielectric loss tangent of each layer (if the other ones have known parameters) or in the whole sample averaging over the layers contribution. Dispersion equations for the considered modes in both types of cavities with three-, two-, or one-layer samples are obtained. The measurement sensitivity and errors in the dielectric constant are discussed. Analytical expressions for the computation of the dielectric loss tangent of the unknown layer in the two directions are presented for each of the considered cavities. The proposed method is applicable in simple laboratory conditions and allows an estimation of the dielectric anisotropy of multilayer materials in many practical cases. The measuring errors for one-layer artificial substrates with thicknesses of 0.25-0.5 mm are approximately 3%-6% for dielectric constants in the interval of 2.0-4.5 and 10%-15% for dielectric loss tangents in the interval of 0.002-0.010. The obtained pair of longitudinal and transversal dielectric parameters can be used in modern structure simulators for more realistic simulations of microwave components, radiating elements, antenna radomes, etc. Three practical examples for three-layer antenna radomes are given for an illustration of the dielectric anisotropy characterization of multilayer samples.
59 citations
TL;DR: In this article, a new technique to measure uniaxial anisotropy in planar substrates is described using a single dual-mode resonator, where each mode of the resonator has a different distribution of horizontal and vertical directed fields.
Abstract: A new technique to measure uniaxial anisotropy in planar substrates is described. The technique uses a single dual-mode resonator. Each mode of the resonator has a different distribution of horizontal (parallel to the substrate surface) and vertical (perpendicular to the substrate surface) directed fields. Using an electromagnetic analysis of the dual-mode resonator, the resonant frequencies of the modes are space mapped to the horizontal and vertical dielectric constants. The space mapping allows the anisotropic dielectric constants to be extracted from the measured resonant frequencies. It is also suggested that this technique can be applied to magnetic uniaxial anisotropy as well as to magnetic and electric loss tangent anisotropy. The dual and quad "RA" resonators are introduced in this paper. A measurement of FR4 (a common anisotropic epoxy-glass weave composite substrate) with a detailed error analysis illustrates the technique.
30 citations
"Concept for equivalent dielectric c..." refers methods in this paper
...Recently other methods have been proposed, based on resonance measurements directly in planar anisotropic structures: by even and odd modes in edgecoupled microstrip lines [9] or in SIW structures [10]....
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