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A thin-layer dielectric and metamaterial unit-cell stack loaded miniaturized SRR-based antenna for triple narrow band 4G-LTE applications
摘要： This article presents the design of a miniaturized dual-band antenna for long-term evolution (LTE) application is presented. In the basic antenna design, split ring resonator was loaded in the radiating plane of the patch and frequency of resonance was further modified with the help of E-shaped stub. The antenna has been fabricated using FR-4 substrate and the measured dual bands at 2.11 and 2.665 GHz are found in a close match with the simulated data. By placing a thin dielectric resonator of permittivity εr = 10.2 and thickness of 1.27 mm, two closely spaced narrow bands are obtained at 2.217 and 2.28 GHz. A novel metamaterial unit-cell having near-zero refractive index is designed and mounted above the dielectric resonator. This stack configuration generates triple narrow frequency band in the LTE 2 GHz spectrum range. The overall size of the proposed antenna is 20 × 25 mm2.
关键词： triple band,split ring resonator,thin layer dielectric resonator,reflection coefficient,patch,unit-cell
更新于2025-09-23 15:23:52
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Effects of the microstructure and density profiles on wave propagation across an interface with material properties
摘要： The characterization of the interphase condition between two materials is current in mechanics. In general, its modeling is achieved by considering an interface with only purely elastic properties. In this paper, following previous works, also inertial interface properties are taken into account. For sufficiently low-frequency regime, we investigate two density profiles (affine and quadratic), for the interphase. Moreover, the interface and the interphase are placed between two solids with different characteristics. The first one is non-dispersive, while for the second one three cases are considered: (a) solid without microstructure, i.e., a Cauchy continuum, (b) solid with microstructure characterized by normal dispersion, i.e., a strain gradient continuum, and (c) by anomalous dispersion. The reflection coefficients are plotted for each case. These results are evaluated with respect to a benchmark finite elements simulation of the finite heterogeneous interphase, and the error is discussed. It is shown that the effects of microstructure can be appreciated at higher frequencies and that the proposed model results to be accurate.
关键词： Strain gradient,Reflection coefficient,Interface,Interphase,Density profiles,Wave propagation
更新于2025-09-23 15:23:52
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[IEEE 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Odessa, Ukraine (2018.9.4-2018.9.7)] 2018 9th International Conference on Ultrawideband and Ultrashort Impulse Signals (UWBUSIS) - Mathematical Model of Transverse Circumferential Slots in Coaxial Line Shield With Nonhomogeneous Dielectric Interior
摘要： Excitation and scattering problem for transverse circumferential slots in a shield of coaxial line with dielectric insert just under the slot has been solved. Internal conductivity is determined including multiple reflections that are caused by dielectric insert of a finite length filling the feeder cross-section up. Formulas for radiation and reflection coefficients are presented.
关键词： dielectric insert,circumferential slot,reflection coefficient,radiation coefficient,line,conductivity,magnetomotive,force,coaxial
更新于2025-09-23 15:21:21
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A Domain Decomposition Finite Element Method for Modeling Electromagnetic Scattering from Rough Sea Surfaces with Emphasis on Near-Forward Scattering
摘要： A high fidelity full-wave simulator is presented to perform numerical experiments for rough sea scattering problem by considering different polarizations, frequencies, grazing angles, wind speeds and sea surface spectra. The simulator is based on a novel Finite Element Domain Decomposition (FEDD) method for solving the problem of two dimensional electromagnetic scattering over one-dimensional sea surface. This non-iterative method partitions the computational domain into a number of overlapping subdomains and solves each domain individually by employing the Locally-Conformal Perfectly Matched Layer (LC-PML) at the truncation boundaries. LC-PML has a unique feature such that it can be applied to irregular domains on the contrary to standard PML methods, and hence inspired the birth of FEDD. The FEDD method is used at each Monte Carlo realization corresponding to a sample from random rough surfaces, and decreases the computational load especially for electrically-large problems. The accuracy and computational efficiency of the method is investigated through several simulations. Using the FEDD method, the statistical behavior of the bistatic Radar Cross Section (RCS) is obtained for both horizontal and vertical polarizations. A special emphasis is given to forward-scattered RCS and the mean reflection coefficient for sea surface especially at low grazing angles, and it is shown that the simulator produces results in agreement with the Ament and Miller-Brown approximations, and experimental data, proving the reliability of the simulation approach. The results are also compared with the standard finite element method and method of moments. Rough sea surfaces are created by using both Pierson-Moskowitz and Elfouhaily spectra.
关键词： Locally-Conformal Perfectly Matched Layer (PML),forward scattering,sea surface,Domain decomposition,Monte Carlo,rough surface scattering,Finite Element Method (FEM),propagation,reflection coefficient,bistatic Radar Cross Section (RCS),multipath
更新于2025-09-23 15:21:21
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Reflection coefficient of HfO <sub/>2</sub> -based RRAM in different resistance states
摘要： Impedance spectra of multiple resistive states in a stable-switching Resistive Random-Access Memory device based on a stack of Ru/HfO2/Zr/W was studied in this work. Using these observations, re?ection-coef?cients were extracted for different resistive states. Clear changes in the re?ection coef?cient for different resistive states were observed. The device in a low resistive state showed a signi?cantly higher re?ection coef?cient compared to its high resistive state. An increasing trend in the re?ection coef?cient was observed as the device state was gradually recon?gured towards lower resistances. Maximum frequency for re?ection increased with the decrease in the device area. The physics behind this observation is attributed to the interplay of oxygen ion transport among the interfacial layer, conductive ?lament, and HfO2-?lm.
关键词： resistive states,impedance spectra,HfO2,RRAM,reflection coefficient
更新于2025-09-23 15:21:21
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Evaluation of ultrasound reflection coefficient measurement result and its uncertainty by the method of linearization
摘要： It is shown that, if the ultrasound amplitudes before (A0) and after(A) application of the test liquid (soybean oil) to the working surface of the acoustic cell are measured using only one (working) channel of the installation, the measurement results become mutually correlated. And if A0 is measured on the reference installation channel and the amplitude A is measured on the working channel of the installation, the measurement results are not mutually correlated. And thus, it becomes possible to use the method of linearization to evaluate the measurement result and its accuracy characteristics (error and / or uncertainty).
关键词： error,uncertainty,ultrasound,acoustic cell,method of linearization,reference,liquid,measurement,working,correlation,reflection coefficient,soybean oil
更新于2025-09-23 15:21:01
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[IEEE 2019 XXIVth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Lviv, Ukraine (2019.9.12-2019.9.14)] 2019 XXIVth International Seminar/Workshop on Direct and Inverse Problems of Electromagnetic and Acoustic Wave Theory (DIPED) - Waveguide Millimeter Wave Measurement Cell with Minimum Reflection Coefficient for Complex Permittivity Determination of Bioactive Liquids
摘要： An original waveguide millimeter wave measurement cell for complex permittivity determination of bioactive high-loss liquids was studied numerically and experimentally. This measurement cell consisted of round metal waveguide, Teflon inserted and glass capillary with liquid under test inside. The main features of the measurement cell are as follows. Waveguide connections (matching elements) to input and output waveguides have minimum reflection coefficient. The capillary with the high loss liquids under test located not in the electromagnetic field maximum as usual, but at an angle to the wave propagation along the waveguide cell. The advantages of such capillary location were discussed in the paper. This waveguide millimeter wave measurement cell was compared with the symmetrical waveguide millimeter wave measurement cell for complex permittivity determination.
关键词： millimeter waves,reflection coefficient,Microwave resonator,complex permittivity,bioactive liquids,frequency spectrum,waveguide
更新于2025-09-16 10:30:52
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[IEEE 2018 IEEE MTT-S International Microwave and RF Conference (IMaRC) - Kolkata, India (2018.11.28-2018.11.30)] 2018 IEEE MTT-S International Microwave and RF Conference (IMaRC) - 3D Frequency Selective Surfaces based on Substrate Integrated Waveguide Technology
摘要： In this paper, a novel design technique for designing 3D frequency selective surfaces (FSS) is proposed based on substrate integrated waveguide (SIW) cavity technology. The proposed design comprises of two tightly coupled FSS elements through the series of periodically spaced metallic vias which are separated a by a finite gap. The structure exhibits passbands characteristics with a relative bandwidth of 14.14%. Further, it exhibits two sharp roll-off performance characteristics on either edges of transmission frequency with two transmission zeros. The parametric study has been conducted to analyze its effect on frequency response of the structure. Furthermore, the material characteristics are derived to analyze the material behavior of the structure.
关键词： 3D FSS,Substrate integrated waveguide,Electromagnetic materials,reflection coefficient,transmission coefficient,EM wave propagation,Frequency selective surface (FSS)
更新于2025-09-12 10:27:22
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Medium Power Application of a Four-Port Reflectometer
摘要： This paper describes an application of a four-port reflectometer system to measure the reflection coefficient of a terminal load from 1 GHz to 2.5 GHz at about 150 W power level. The scattering parameters of the four-port reflectometer measured at low power have been experimentally proved to be applicable at medium power. The measurement results of the four-port reflectometer are presented and analyzed. This measurement method can be used at higher power level.
关键词： Medium Power,Four-Port Reflectometer,reflection coefficient,Directional Coupler
更新于2025-09-10 09:29:36
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[IEEE 2018 48th European Microwave Conference (EuMC) - Madrid, Spain (2018.9.23-2018.9.27)] 2018 48th European Microwave Conference (EuMC) - Extraction of Relative Permittivity from Measured Reflection Coefficient of Dielectric Materials in the Frequency Range 207 – 247 GHz
摘要： This work describes the use of millimetre wave technology to extract the dielectric constants of different types of dielectric materials. The extraction of the dielectric materials is based on measurements (i.e., monostatic measurements) of the reflection coefficient for various dielectric materials. The measurements are done by utilizing a frequency modulated continuous wave radar with a dielectric lens antenna. The investigated materials are broadly utilized as a part of our everyday life. The fundamental dielectric materials outcomes are done accompanying materials: Polytetrafluoroethylene (PTFE), mainly Teflon, nylon, and. The measurements are done in the frequency range from 207 GHz to 247 GHz.
关键词： reflection coefficient,material characteristics,corner reflector,millimeter wave length,dielectric materials,permittivity,measurement,lens antenna
更新于2025-09-04 15:30:14