Multilayer Resonator Research Articles

Improvement of noise reduction performance in bellows using multilayer perforated panels

When the speed of a railway vehicle increases, the level of noise inside the vehicle inevitably increases as well, which is a major cause of discomfort to passengers. The most effective method is to improve the overall noise reduction performance of a vehicle. In particular, the gangway of the railway vehicle is made of silicone rubber; therefore, its noise reduction performance is inferior to that of other components of the vehicle. Thus, it is essential to improve the interior noise performance of railway vehicles. This study aims to reduce the noise in the low-frequency region of a railway vehicle gangway. It examines the applicability of the multi-layered resonance type panel, which has not been previously applied to the bellows in railway vehicles. In particular, the transmission loss was improved by changing the structure without filling the bellows with sound-absorbing material. First, a theoretical review of the noise reduction performance of a perforated multilayer structure was performed. Based on this, the major design parameters of the perforated multilayer structure that are effective in reducing noise in the low-frequency region of the bellows were derived. Through this, it was confirmed that in the multilayered structure, the hole diameter of 1 mm was effective in increasing the transmission loss in the low-frequency region, and the transmission loss was improved at 1% of the porosity. In addition, through a simple two-dimensional analysis model, it was confirmed that the transmission loss of the porous panel was improved at low frequencies of 100 to 400 Hz. Based on this result, a gangway with perforated multilayer structures was developed and tested. Through this verification test, it was confirmed that the noise performance of 9.2 dB was an improvement in the low frequency range of 100 Hz.

Designing of Optical Filter Based on Modelling Procedure of Multilayer Quadruple Combined Micro Ring Resonator (MQCMRR) Structure with 2 × 3 I/O Bus Waveguides

A new and advanced ring resonator model with its performance analysis as an optical filter is presented in this paper. The recommended model composites of four asymmetrical micro rings with two input and three output bus waveguides. This multilayer quadruple combined micro ring resonator (MQCMRR) structure is modelled in Z-domain by the application of delay lines and Masons gain principle. This model is confined in three layers by adopting series coupling as well as vertical coupling. Various performance parameters are evaluated like free spectral range (FSR), group delay (GD), dispersion (DP), full-width-half-maxima (FWHM), and Q-factor, by the analysis of spectral response in MATLAB environment. Design of optical couplers, as well as the study of field transmission through the rings and waveguides, are carried out by the finite-difference-time-domain (FDTD) method. Performance in optical communication system of this recommended ring resonator-based optical filter is investigated through a simulation program which is done by OptiSystem16.0 software. Data transmission performance is graphically shown by an eye diagram. For this proposed model high FSR and zero crosstalk is achieved at all output port. All the important consequences like large FSR, zero crosstalk, high data handling capability, perfect field transmission and exact open eye diagram certify the smashing performance of this architecture in the optical communication system as an optical add-drop filter.

Planar acoustic scattering by a multi-layered split ring resonator.

The problem of two-dimensional acoustic scattering of time-harmonic plane waves by a multi-ringed cylindrical resonator is considered. The resonator is made up of an arbitrary number of concentric sound-hard split rings with zero thickness. Each ring opening is oriented in any direction. The acoustics pressure field in each layered region enclosed between adjacent rings is described by an eigenfunction expansion in polar coordinates. An integral equation/Galerkin method is used to relate the unknown coefficients of the expansions between adjacent regions separated by a ring. The multiple scattering problem is then formulated as a reflection/transmission problem between the layers, which is solved using an efficient iterative scheme. An exploration of the parameter space is conducted to determine first, the conditions under which the lowest resonant frequency can be minimised, and second, how non-trivial resonances of the multi-ring resonators can be explained from those of simpler arrangements, such as a single-ring resonator. It is found here that increasing the number of rings while alternating the orientation lowers the first resonant frequency, and exhibits a dense and nearly regular resonant structure that is analogous to the rainbow trapping effect.

High numerical aperture microwave metalens.

The numerical aperture (NA) of a lens determines its focusing resolution capability and the maximum light collection or emission angle. In this Letter, an ultrathin high NA metalens operating in the microwave band is designed and demonstrated both numerically and experimentally. The proposed element is constructed by a multi-layer complementary split ring resonator, which can cover full 2π phase shift simultaneously with high transmission magnitude by varying its radius gradually. The numerical and experimental results reveal that the designed ultrathin (thickness is only ∼0.23λ) metalens can focus normal incident microwave efficiently to a spot of full width at half-maximum (FWHM) as small as ∼0.54λ with a corresponding high NA exceeding 0.9. Besides, the high NA metalens also possesses a relatively large focusing efficiency with a peak 48% within considered broad frequency range from 7.5 to 10 GHz. The performances of the presented metalens can be comparable or even superior to nowadays high-quality optical metalenses and represent an important step to develop a high-performance metalens in low spectrum. Besides, it can greatly facilitate the development of some novel miniaturized devices like a high-gain low profile scanning antenna, an ultra-compact retroreflector, and cloaks.

Free control of far-field scattering angle of transmission terahertz wave using multilayer split-ring resonators’ metasurfaces

To enhance transmission efficiency of Pancharatnam-Berry (PB) phase metasurfaces, multilayer split-ring resonators were proposed to develop encoding sequences. As per the generalized Snell’s law, the deflection angle of the PB phase encoding metasurfaces depends on the metasurface period’s size. Therefore, it is impossible to design an infinitesimal metasurface unit; consequently, the continuous transmission scattering angle cannot be obtained. In digital signal processing, this study introduces the Fourier convolution principle on encoding metasurface sequences to freely control the transmitted scattering angles. Both addition and subtraction operations between two different encoding sequences were then performed to achieve the continuous variation of the scattering angle. Furthermore, we established that the Fourier convolution principle can be applied to the checkerboard coded metasurfaces.

Multi-layer optical fiber surface plasmon resonance biosensor based on a sandwich structure of polydopamine-MoSe2@Au nanoparticles-polydopamine.

An all-optical fiber multi-layer surface plasmon resonance (SPR) biosensor based on a sandwich structure of polydopamine-MoSe2@Au nanoparticles-polydopamine (PDA-MoSe2@AuNPs-PDA) was designed for the detection of specific immunoreactions. By optimizing the multi-layer structure and the ratio of MoSe2: AuNPs, a sensitivity of 5117.59 nm/RIU has been obtained, which is more than double that of the only Au-filmed optical fiber SPR sensor. A large surface area was produced by integrating the MoSe2 primitive unit cell and the AuNPs into a hybrid plasmonic nanostructure of MoSe2@AuNPs, leading to optical fiber SPR signal amplification. The nanostructure of MoSe2@AuNPs was surrounded by the PDA layer to guarantee the efficient immobilization of the protein molecules on the optical fiber by strong covalent bond. This biosensor achieved a detection limit of 54.05 ng/mL for detecting the goat-anti-rabbit IgG, which demonstrated enhancements of 12.1%, 23.3% and 184.6% in comparison with three reported SPR biosensors decorated with PDA-AuNPs-PDA, PDA and Cysteamine-MoSe2@AuNPs-Cysteamine nanostructure, respectively. This biosensor achieved favorable selectivity and outstanding sensitivity compared with the reported SPR immuno-sensors, which will provide a miniaturized, rapid-response and label-free optical fiber bio-sensing platform for clinical diagnosis in the future.

Multi-resonant refractory prismoid for full-spectrum solar energy perfect absorbers.

In this work, a feasible way for perfect absorption in the whole solar radiance range is numerically demonstrated via the multiple resonances in a 600-nm-thick refractory prismoid. Under the standard AM 1.5 illumination, the measured solar energy absorption efficiency reaches 99.66% in the wavelength range from 280 nm to 4000 nm, which indicates only a rather small part of solar light (0.34%) escaped. The record harvesting efficiency directly results from the near-unity absorption for the multi-layer refractory resonators, which can simultaneously benefit from the multi-resonant behaviors of the structure and the broadband resonant modes by the material intrinsic features. The absorption including the intensity and frequency range can be adjusted via the structural features. These findings can hold wide applications in solar energy related optoelectronics such as the thermal-photovoltaics, photo-thermal technology, semiconductor assisted photo-detection, ideal thermal emitters, etc.

Elastothermodynamic damping modeling of three-layer Kirchhoff–Love microplate considering three-dimensional heat conduction

Elastothermodynamic damping is one of the most important energy loss mechanisms in micro/nano mechanical resonators, which is related to the high sensitivity and high resonance frequency characteristics of resonators. With the wide application of resonators, multilayer microplate resonators have been applied. In this paper, the elastothermodynamic damping models of three-layer of Kirchhoff–Love microplate under three typical boundary support conditions of Clamped-Clamped-Clamped-Clamped (C-C-C-C), Clamped-Free-Clamped-Free (C-F-C-F) and Clamped-Free-Free-Free (C-F-F-F) are established. Firstly, the thermoelastic mechanical equations of the microplate are given, and then the three-dimensional temperature distribution functions of the microplate are obtained based on the generalized orthogonal function method. Finally, the elastothermodynamic damping models are established based on the composite multilayer plate theory. The model in this paper is compared with the previous model and the finite element results.

Analytical modeling of mechanical behavior for MEMS/NEMS-based single-clamped multilayer resonators with symmetrical complex shapes

Several micro/nano-electromechanical systems (MEMS/NEMS) devices are composed by complex-shaped multilayer resonators such as energy harvesters, gas and biological sensors, magnetic field sensors, accelerometers, and viscosity sensors. These devices require analytical models to predict the best mechanical performance, improving their sensitivity and resolution. Here, we present the analytical modeling to determine the mechanical behavior of MEMS/NEMS-based single-clamped multilayer resonators with symmetrical complex shapes. This modeling can estimate the first bending resonant frequency and out-plane deflections of multilayer resonators using the Rayleigh and Macaulay methods, as well as the Euler–Bernoulli beam theory. In addition, the quality factors of these multilayer resonators are calculated considering the air damping at atmospheric pressure. Also, finite element method (FEM) models are developed to obtain the mechanical behavior of the resonators. The results of our analytical models agree well with those of FEM models and experimental data reported in the literature. The proposed analytical modeling can be used to enhance the mechanical response of MEMS/NEMS devices formed by multilayer resonators with symmetrical complex cross-sections.

Extraordinary acoustic transmission of a decorated window without ventilation

We introduce a kind of acoustic metamaterial, which can greatly enhance the transmission at subwavelength ranges and keep its hyaline and air-proof characteristics simultaneously. In contrast to the state of the art, this originally conceived passive metamaterial makes full use of the resonance of glass plates without any complex or expensive materials. We provide the design of the decorated window, numerical simulation, and experimental demonstrations for this kind of metamaterial and analyze the underlying physical mechanism. Furthermore, we show that more transmission peaks can be realized by introducing multilayer resonance coupling of this decorated window. This meta-window should have many potential applications where both the sound and visible light transmission are required without any ventilation.

Multianalyte sensing analysis with multilayer photonic crystal fiber-based surface plasmon resonance sensor

In this work, we proposed multianalyte multichannel Photonic Crystal Fiber (PCF)-based Surface Plasmon Resonance sensor with gold- and silver-doped plasmonic layers. The Full Vectorial Finite Element Method (FV-FEM) with perfectly matched layers (PML) are employed for numerical analysis of the proposed sensor. The key propagation features, such as confinement loss, resonance condition, resolution, and sensitivity of the proposed sensor, have been reported for all possible refractive index variations. According to the spectral sensitivity analyses, the average sensitivities for fixed RI values are obtained as 4100 nm/RIU and 3820 nm/RIU for Ch1 and Ch2, respectively. On the other hand, results for varying RI values are obtained as 3600 nm/RIU and 3700 nm/RIU for Ch1 and Ch2, respectively. Moreover, the maximum average sensitivity of proposed sensor reaches to 4250 nm/RIU for varying RI at Ch2 and 4200 nm/RIU for varying RI at Ch1.

A novel method to improve the measurement accuracy of multilayer surface plasmon resonance sensor

In this paper, a novel method to improve the measurement accuracy of multilayer surface plasmon resonance (SPR) sensor is proposed. Based on the Kretschmann SPR sensor, the measurement layer is transferred from the outermost layer to the inside of the structure (in the form of prism-metal-measurement-dielectric layer), the new structure shows excellent linear relationship between the refractive index (RI) and the resonance wavelength with the linear fitting coefficient improved from 0.97048 to 0.99904, and the measurement error reduced by 96.75 %, which can greatly improves the measurement accuracy. In the simulation of the five-layer, six-layer and seven-layer structure, it is verified that the conclusion of four-layer structure is also applicable to multilayer structures, the detailed analysis and explanation are also discussed. As an example, magnetic fluid (MF) film is selected as the measurement layer to demonstrate the performance of the designed structure. Parameters of the structure were optimized by simulation, the optimal thickness of the MF layer is 120 nm and the optimal RI of dielectric layer is 1.35. With these optimized parameters, the measurement accuracy is greatly improved and the measurement sensitivity of magnetic field is 5nm/mT. The idea is also expected to be applied to other types of SPR sensors to achieve higher measurement accuracy.

In brief

PAGE 771 Researchers from Vietnam present a study on how multiple users affect the performance of NOMA networks over α−κ−μ fading channels. The exact expressions in terms of ergodic capacities and outage probabilities are derived, along with a comparison with OMA under such shadowed fading. PAGE 787 A study into how double-layer electron transporting layers affects the efficiency of lead sulfide quantum dots solar cells is presented. A device with power conversion efficiency of 10.6% is achieved due to the enhancement in open circuit voltage. The loss-in-potential is reduced by 80 mV by use of the double-layer ZnO/SnO2 electron transporting layer. Ergodic Rate (BCPU) versus the average transmit SNR. PAGE 753 A correction algorithm for time-interleaved analog-to-digital converters (TIADAC) in order to solve the problem of calibration failure caused by frequency timing mismatch exceeding sub-Nyquist frequency is presented. The proposed technique consumes less hardware and works well without employing a band-pass filter or reference channel. Simulations show the calibration is effective throughout the entire Nyquist band of TIADC. Schematic of PbS QDs solar cell fabricated on ZnO/SnO2 ETL. PAGE 780 A novel out-of-plane integration of multilayer strip resonators is proposed. The structure retains the merit of traditional in-plane integrated devices whilst achieving the same amount of coupling with smaller horizontal space between resonators. Overall a 52.4% reduction in size is achieved whilst comparable performance is maintained. Block diagram of improved calibration direction correction algorithm. PAGE 782 German and British researchers present an implementation of two amplifiers in a commercial, flexible a-IGZO TFT technology. The amplifiers significantly outperform previously flexible a-IGZO TFT amplifiers in terms of bandwidth, gain-bandwidth product, unity-gain frequency, power consumption and area. The input sensitivity of a-IGZO TFT wireless systems can be increased considerably by using the amplifier circuit. Measurement of re-designed band-pass filter, samples in inset photograph. Schematic of CS amplifier.

Mesoporous Thin Films for Acoustic Devices in the Gigahertz Range

The coherent manipulation of acoustic waves on the nanoscale usually requires multilayers with thicknesses and interface roughness defined down to the atomic monolayer. This results in expensive devices with predetermined functionality. Nanoscale mesoporous materials present high surface-to-volume ratio and tailorable mesopores, which allow the incorporation of chemical functionalization to nanoacoustics. However, the presence of pores with sizes comparable to the acoustic wavelength is intuitively perceived as a major roadblock in nanoacoustics. Here we present multilayered nanoacoustic resonators based on mesoporous SiO$_2$ thin-films showing acoustic resonances in the 5-100 GHz range. We characterize the acoustic response of the system using coherent phonon generation experiments. Despite resonance wavelengths comparable to the pore size, we observe for the first time unexpectedly well-defined acoustic resonances with Q-factors around 10. Our results open the path to a promising platform for nanoacoustic sensing and reconfigurable acoustic nanodevices based on soft, inexpensive fabrication methods.

Intra- and inter-observer reproducibility of multilayer cardiac magnetic resonance feature tracking derived longitudinal and circumferential strain.

Multilayer strain measurement with cardiac magnetic resonance feature tracking (CMR-FT) allows independent assessment of endocardial and epicardial strain. This novel method of layer-specific quantification of myocardial deformation parameters provides greater insight into contractility compared to whole-layer strain analysis. The clinical utility of this technique is promising. The aim of this study is to investigate the intra- and inter- observer reproducibility of CMR-FT derived multilayer global longitudinal strain (GLS) and global circumferential strain (GCS) parameters in the setting of normal cardiac function, cardiac pathology, and differing MRI field strengths. We studied 4 groups of 20 subjects, comprising of patients with dilated cardiomyopathy, ischemic heart disease, and patients without cardiac pathology at both 1.5 and 3 T. Quantitative measures of whole-layer and multi-layer longitudinal and circumferential strain were calculated using CMR-FT software. Intraclass correlation coefficients (ICC) for intraobserver reproducibility of endocardial, epicardial, and whole-layer measurements of GLS were 0.979, 0.980, and 0.978 respectively, and those for GCS were 0.986, 0.977, and 0.985. ICCs for inter-observer reproducibility of endocardial, epicardial, and whole-layer measurements of GLS were 0.976, 0.970, and 0.976, and those for GCS were 0.982, 0.969, and 0.981. Bland Altman analysis showed minimal bias and acceptable limits of agreement (LOA) within each patient subgroup and the overall cohort. Circumferential and longitudinal strain parameters were equally reproducible in the overall cohort. CMR-FT derived multilayer measurements of longitudinal and circumferential strain demonstrate high intra- and inter- observer reproducibility, with suitability for use in clinical practice.

An ultra-broadband terahertz metamaterial coherent absorber using multilayer electric ring resonator structures based on anti-reflection coating.

We propose a method for achieving THz ultra-broadband coherent absorption using the anti-reflection theory of metamaterials. The metamaterial absorber consists of a periodic array of electric ring resonators with a multilayered structure which form the desired refractive index dispersion and provide continuous anti-reflection over a wide frequency range. The destructive interference mechanism and resonance absorption of the absorber are determined by simulation analysis and numerical simulation. Simulation results show that the absorption bandwidth is almost 8.02 THz (absorption rate >90%) over the entire terahertz band (0.1 THz-10 THz). This design provides an effective and viable method for constructing broadband absorbers for stealth technology and the construction of enhanced transmittance devices.

Theoretical Investigation of Multilayer Ti3C2Tx MXene as the Plasmonic Material for Surface Plasmon Resonance Sensors in Near Infrared Region

The multilayer Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> MXene-based surface plasmon resonance (SPR) sensors are theoretically discussed with high figure of merit (FOM) (304 RIU-1) in near infrared region. The result shows that the multilayer Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> MXene, a metallike material, can be used to produce a strong SPR signal and further applied to detect the change in refractive index of sensing medium. Comparing to the conventional SPR sensor based on Au thin film (50 nm) at the visible range, the FOM of the proposed MXene-based SPR sensor has been improved by 7.8 times. Our study demonstrates that the multilayer Ti <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> MXene can be developed as a new surface plasmon polariton (SPP) material to apply in SPR sensor.

Piezoelectric Actuators and Motors: Materials, Designs, and Applications

AbstractPiezoelectric actuators are unique driving force‐generation devices, which can transfer input electric energy into force, displacement, or movement outputs efficiently and precisely via piezoelectric effect‐based electromechanical coupling instead of electromagnetic induction. In comparison with traditional electromagnetic actuators, the most important features of the piezoelectric actuators are their compact size, flexible design, and ability to provide nanometer or sub‐micrometer positioning. Here, recent progress in nonresonance piezoelectric actuators including multilayer ceramic actuators, step motors, inertial motors, and resonance ultrasonic motors, such as linear motors, rotary motors, multidegree of freedom motors, and microelectromechanical system actuators, is comprehensively presented. The working principles and properties of these actuators are explained, and the piezoelectric materials and configurations, fabrication, and applications are provided. Furthermore, from the aspects of materials, designs and applications, challenges and outlooks for future developments of piezoelectric actuators and motors are also discussed.

Synthesis of single phase MgTiO3 and influence of Sn4+ substitution on its structural, dielectric and electrical properties

In this work, synthesis of single-phase MgTiO3 and Mg(Ti0.95Sn0.05)O3 ceramics through conventional solid state mixed oxide route using Mg(OH)2 or MgO as raw material was investigated. The phase purity of prepared specimens was examined using X-ray diffraction; bond characteristics were determined via Raman spectroscopy, dielectric properties at low frequency were measured by Impedance spectroscopy and dielectric properties at microwave frequency were measured by vector network analyzer. The properties of Mg(OH)2 based ceramics were also compared to that of MgO based ceramics in frequency range of 10 kHz-3 MHz and temperature range of 298–468 K. It was observed that Mg(OH)2 based materials exhibited not only low losses (tan δ) and low relative permittivity (ϵr) but also possessed smaller value of temperature coefficient of resonant frequency (τf) in comparison to that of MgO based materials. Dielectric and electrical properties of MgTiO3 were further improved by partial replacement of tetravalent cations Ti4+ with Sn4+. The mechanism of electrical conduction for the synthesized specimens was also studied using Jonscher power law and activation energy was evaluated using Arrhenius equation. Best dielectric properties at room temperature in 10 kHz-3 MHz frequency range were displayed by Mg(OH)2 based Mg(Ti0.95Sn0.05)O3 compound having tan δ of 2.32 × 10−4, ϵr of 14.61 and τf of −39.7 ppm/K at 100 kHz frequency. At 15 GHz Mg(OH)2 based Mg(Ti0.95Sn0.05)O3 exhibited tan δ of 2.73 × 10−2 and ϵr of 14.12. This material could be utilized for fabrication of multilayer capacitors, dielectric resonators, filters, antennas, buffer layers and protective coatings.

Z-domain modeling approach of a multilayer sextuple-coupled micro-ring resonator with 1 × 5 input-output bus waveguides as optical filters.

This paper introduces the modeling approach of a new micro-ring resonator configuration composite of six asymmetrical rings with one input and five output bus waveguides. This multilayer sextuple-coupled micro-ring resonator (MSCMRR) is modelled in the z domain by practicing the delay line signal approach and Mason's gain formula. Both lateral coupling and vertical coupling are used to design this MSCMRR structure to confine it up to four layers. Performance analysis is carried out in a MATLAB platform with the graphical representation of performance parameters like free spectral range (FSR), group delay, dispersion, full width at half-maximum, etc. The optical couplers of the proposed model are also designed by the finite-difference time-domain (FDTD) method. Electric field propagation through the rings and the waveguides are also studied by FDTD. The proposed structure offers different values of high FSR with zero crosstalk at every output port that ensures the quality application of this proposed model as an optical add-drop filter in an optical communication network.