Coupling In Multilayers Research Articles

Ultrafast evanescently coupled waveguide MUTC-PDs with high responsivity

Novel evanescently coupled waveguide modified uni-traveling carrier photodiodes (MUTC-PDs) employing a thick multi-layer coupling waveguide are reported. To improve the optical-to-electrical (O/E) conversion efficiency, a thick multi-layer coupling waveguide with a gradually increased refractive index from the bottom layer to the absorption layer is utilized. The refractive index profile facilitates the upward transmission of incident light into the absorption region, thereby enhancing the evanescent coupling efficiency. Meanwhile, the coupling waveguide, with a total thickness of 1.75 µm, expands the mode field diameter, thereby reducing the input coupling loss. Additionally, the top layer of the coupling waveguide also serves as the drift layer. This configuration facilitates efficient light absorption within a short PD length, thus ensuring ultrawide bandwidth and high O/E conversion efficiency simultaneously. Without an additional spot size coupler or anti-reflection coating, the measured responsivity is as high as 0.38 A/W for the PD with an active area of 5 × 6 µm2. Meanwhile, an ultrawide 3-dB bandwidth of 153 GHz has been demonstrated.

Quantized dynamic event-triggered control for fixed/preset-time bipartite synchronization of memristor-based discontinuous multi-layer signed networks

This study addresses the fixed/preset-time bipartite synchronization (FTBS/PTBS) of memristor-based discontinuous multi-layer signed networks via quantized dynamic event-triggered control (ETC). Firstly, a memristor-based neural network model incorporating multi-layer coupling structures, signed networks and discontinuous activations is built. Subsequently, by designing two quantized dynamic ETC strategies without the linear feedback term, the FTBS and PTBS of the considered networks are discussed, and it is proved that Zeno behavior can be ruled out. In contrast to the previous static ETC mechanism, the introduced internal dynamic variable can significantly decrease the triggering times and further save communication resources. Lastly, three numerical examples are offered to verify the correctness and practicability of the theoretical analysis.

Project Group Program Generation and Decision Making Method Integrating Coupling Network and Hesitant Fuzzy

Modern urban construction relies on a large number of projects. Project groups are an effective way to manage a large number of projects. In view of the current lack of scientific methods for constructing and evaluating project group programs, which are mainly based on subjective experience, this article proposes a scientific method for project group program generation and decision-making. The method proposed in this article applies a multi-layer coupling network to the modeling of project groups and divides projects into planning projects and execution projects to form a heterogeneous coupling network. Then, starting from the principle of project information dissemination, the evaluation indicators of the project group program were defined, and finally, the hesitant fuzzy decision-making method was used to assist in decision making. This article can provide a new method for project group construction and management, and provide strong support for the construction of smart cities and digital governments.

Densely packed skyrmions stabilized at zero magnetic field by indirect exchange coupling in multilayers

Room-temperature stabilization of skyrmions in magnetic multilayered systems results from a fine balance between several magnetic interactions, namely, symmetric and antisymmetric exchange, dipolar interaction and perpendicular magnetic anisotropy as well as, in most cases, Zeeman through an applied external field. Such field-driven stabilization approach is, however, not compatible with most of the anticipated skyrmion based applications, e.g., skyrmion memories and logic or neuromorphic computing, which motivates a reduction or a cancellation of field requirements. Here, we present a method to stabilize at room-temperature and zero-field, a densely packed skyrmion phase in ferromagnetic multilayers with moderate number of repetitions. To this aim, we finely tune the multilayer parameters to stabilize a dense skyrmion phase. Then, relying on the interlayer electronic coupling to an adjacent bias magnetic layer with strong perpendicular magnetic anisotropy and uniform magnetization, we demonstrate the stabilization of sub-60 nm diameter skyrmions at zero-field with adjustable skyrmion density.

Characterization of Multilayer Coupling Based on Square Complementary Split Ring Resonator for Multiport Device Implementation.

The advent of context-aware environments and related applications demands a high degree of connectivity, with new spectral bands and related radio resource management functionalities in the current 5G bands and foreseen in future 6G wireless communication systems. This, in turn, poses new challenges in the implementation of wireless transceivers and radiating systems, in terms of device integration, miniaturization and element isolation, among others. High-performance miniature devices are presented and studied in this work, aided by metamaterial-inspired complementary resonators. A single particle is used to build a single layer, double layer, double frequency resonators and power dividers. A complete characterization of each equivalent circuit is also analyzed, showing great agreement between analytical circuit models and full-wave electromagnetic simulations. By adding more particles, different diplexers and triplexers in the multi-layer configuration are proposed. The flexibility in the design is the key advantage, as all devices are easily tunable and the output lines can be built in different layers, enabling frequency scalability from RF to millimeter wave ranges. Nevertheless, they are only a sample of all possible combinations of devices that can be designed for integration in future wireless communication systems.

When multilayer links exchange their roles in synchronization.

Real world networks contain multiple layers of links whose interactions can lead to extraordinary collective dynamics, including synchronization. The fundamental problem of assessing how network topology controls synchronization in multilayer networks remains open due to serious limitations of the existing stability methods. Towards removing this obstacle, we propose an approximation method which significantly enhances the predictive power of the master stability function for stable synchronization in multilayer networks. For a class of saddle-focus oscillators, including Rössler and piecewise linear systems, our method reduces the complex stability analysis to simply solving a set of linear algebraic equations. Using the method, we analytically predict surprising effects due to multilayer coupling. In particular, we prove that two coupling layers-one of which would alone hamper synchronization and the other would foster it-reverse their roles when used in a multilayer network. We also analytically demonstrate that increasing the size of a globally coupled layer, that in isolation would induce stable synchronization, makes the multilayer network unsynchronizable.

Origin of noncollinear magnetization coupling across RuX layers

We present a simple atomistic model for the description of noncollinear coupling in magnetic multilayers with hybrid spacer layers made of Ru alloyed to ferromagnetic atoms such as Fe. In contrast to previous analytical and micromagnetic models that explain the noncollinear coupling by means of lateral fluctuations in the coupling constant, the presented model accounts for atom-atom coupling in all three spatial dimensions within the spacer layer. The model is able to accurately predict the dependence of the macroscopic bilinear and biquadratic coupling constants on the spacer-layer composition and thickness, showing much better quantitative agreement than lateral-fluctuation models. Moreover, it predicts that the noncollinear coupling is virtually independent of the exchange stiffness in the ferromagnetic layers, which goes beyond the predictions of previous models. This prediction is validated by experimental measurements.

A Compact Dual Linearly-Polarized Single-Plane Monopulse Antenna Array Based on SIW and Strip-Line Feed

A compact dual linearly polarized monopulse antenna array is proposed in this article. The size of the antenna array is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.13\lambda _{0} \times 4.38\lambda _{0}$ </tex-math></inline-formula> , and it consists of two comparators, multilayer coupling slots, and a group of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times $ </tex-math></inline-formula> 4 square patches. By using high-order-mode cavities and integrating the feeding network with the radiating part, the size of the antenna is considerably reduced. A prototype of the proposed antenna is fabricated and evaluated to the feasibility of the design. The measured total impedance bandwidth for four ports is 1.6% (18.65–18.95 GHz). The peak gains of the sum pattern with vertical and horizontal polarization are greater than 16.02 and 14.92 dBi, respectively. The null depths of the difference pattern at 18.8 GHz are less than −32 dB. The measurement results are in good agreement with the simulation results.

COVID-19 Spread Simulation in a Crowd Intelligence Network

In this paper, the Crowd Intelligence Network Model is applied to the simulation of epidemic spread. This model combines the multi-layer coupling network model and the two-stage feedback member model to study the epidemic spread mechanisms under multiple-scene intervention. First, this paper establishes a multi-layer coupled network structure based on the characteristic of Social Network, Information Network, and Monitor Network, namely, the Crowd Intelligence Network structure. Then, based on this structure, the digital-self model, which has a multiple-scene effect and two-stage feedback structure, is designed. It has an emotional state and infection state quantified by using attitude and self-protection levels. This paper uses the attitude level and self-protection level to quantify individual emotions and immune levels, and discusses the impact of individual emotions on epidemic prevention and control. Finally, the availability of the Crowd Intelligence Network Model on the epidemic spread is verified by comparing the simulation trend with the actual spread trend of COVID-19.

Design of a Broadband Switchable Active Frequency Selective Surfaces Based on Modified Diode Model

In this letter, a broadband switchable active frequency selective surfaces (AFSSs) is presented, and the proposed structure is comprised of three metallic layers and two Rogers RT5880 substrates. In order to realize broadband transmission, a second-order bandpass filter is constructed, and the multilayer coupling effect is utilized. A modified equivalent circuit model of the p-i-n diode is proposed to reduce the simulation error and improve the design accuracy. By controlling the bias voltage of the p-i-n diodes, two completely different functions are realized. At the function of dual-polarized shielding, the shielding bandwidth is 2–18 GHz, and the transmission bandwidth is 8.2–10.5 GHz with a fractional bandwidth of 24.6% at the function of dual-polarized transmission. A prototype has been fabricated and measured, and the measurement results are in good agreement with the simulation results, indicating that the AFSSs has good polarization stability for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">X</i> -band radar applications.

A design of broadband bandpass frequency selective surface

AbstractIn this paper, a broadband frequency selective surface (FSS) based on a multilayer coupling cascade is presented. The overall structure consists of three metallic layers and two dielectric substrates. In addition, a crosspatch terminated with an E‐shaped structure and a gradient cross structure with a slot is introduced in the middle metallic layer to control the transmission zero and extent of the current path, respectively. The unit cell periodicity is about 0.27 , and the overall thickness of the dielectric layer is about 0.087 . Prototypes of the proposed FSS are designed and simulated, and an equivalent circuit model is developed to explain the mechanism further. Finally, the FSS prototype works at the center frequency of 12.2 GHz with a relative −0.5 dB bandwidth of 70% and a relative −3dB bandwidth of 104%. The frequency responses are relatively stable with the variation of incidence angles from 0° to 60°.

Evolution of prosocial behaviours in multilayer populations.

Human societies include diverse social relationships. Friends, family, business colleagues and online contacts can all contribute to one's social life. Individuals may behave differently in different domains, but success in one domain may engender success in another. Here, we study this problem using multilayer networks to model multiple domains of social interactions, in which individuals experience different environments and may express different behaviours. We provide a mathematical analysis and find that coupling between layers tends to promote prosocial behaviour. Even if prosociality is disfavoured in each layer alone, multilayer coupling can promote its proliferation in all layers simultaneously. We apply this analysis to six real-world multilayer networks, ranging from the socio-emotional and professional relationships in a Zambian community, to the online and offline relationships within an academic university. We discuss the implications of our results, which suggest that small modifications to interactions in one domain may catalyse prosociality in a different domain.

Influence of Cr interlayer with different thickness on transition of magnetoresistance effect of Gd/FeCo thin films

As one of the most representative features characterizing the spin valve structure, magnetoresistance is an important method to study the interlayer coupling in multilayers. Considering the induced magnetism of rare earth at room temperature due to the coupling and magnetic proximity effect in the structure of rare earth/magnetic transition metal, an intermediate nonmagnetic metal can be inserted to form the spin valve structure to regulate the interlayer coupling, which expands the scope of applications of rare earth in spintronics. In this work, the interlayer exchange coupling and interfacial effects of Gd (4 nm)/Cr (&lt;i&gt;t&lt;/i&gt;&lt;sub&gt;Cr&lt;/sub&gt;)/FeCo (5 nm) trilayers with different Cr layer thickness (&lt;i&gt;t&lt;/i&gt;&lt;sub&gt;Cr&lt;/sub&gt;) are studied by means of in plane magnetoresistance. Compared with FeCo film, Gd/FeCo film obtains more obvious anisotropic magnetoresistance. While the magnetoresistance value obtained for the configuration of &lt;i&gt;I&lt;/i&gt;⊥&lt;i&gt;H&lt;/i&gt; shows a minimum value at the peak due to the insertion of Cr layer, and this minimum value becomes more pronounced with the increase of &lt;i&gt;t&lt;/i&gt;&lt;sub&gt;Cr&lt;/sub&gt;. When&lt;i&gt; t&lt;/i&gt;&lt;sub&gt;Cr&lt;/sub&gt; = 3 nm, the negative spin valve effect almost totally overcomes the anisotropic-magnetoresistance effect. Different spin asymmetries of scattering that are formed in FeCo layer and Cr/Gd layers are mainly responsible for creating the negative spin valve magnetoresistance, in which the resistance becomes smaller near the coercive, while the resistance becomes larger at high field parallel to magnetic moment. The oscillation of magnetoresistance with &lt;i&gt;t&lt;/i&gt;&lt;sub&gt;Cr&lt;/sub&gt; at &lt;i&gt;I&lt;/i&gt; // &lt;i&gt;H&lt;/i&gt; and the hysteresis loops at 5 K further confirm the existence of interlayer coupling both at room temperature and 5 K.

Ultra-Wideband Compact Millimeter-Wave Printed Ridge Gap Waveguide Directional Couplers for 5G Applications

A compact ultra-wideband printed ridge gap waveguide directional couplers for millimeter-wave applications are presented in this paper. A multi-layer coupling technique between two resonant patches is adopted to achieve a wider operating bandwidth with better amplitude and phase balance compared to single-layer technology. For this purpose, a systematic design procedure is deployed to achieve several coupling values in the range of 3-10 dB over a wide frequency bandwidth centered at 30 GHz. A 3-dB hybrid coupler is fabricated and measured, where a bandwidth of 12 GHz (about 38 % fractional bandwidth) from 25 GHz to 37 GHz is achieved. In addition, the phase balance is 90&#x00B0; &#x00B1; 5&#x00B0; over 38% fractional bandwidth with an amplitude balance of 3.4 &#x00B1; 0.5 dB over a 26.5% centered at 30 GHz. The proposed couplers with superior characteristics such as compactness, low loss, and low dispersion are considered a good candidate for millimeter-wave applications such as the fifth-generation (5G) wireless communications.

Widebandlog‐periodicphase shifters

This paper presents concept of wideband log-periodic phase shifter (LPPS) and also three novel microstrip phase shifters using a log-periodic structure for the first time. The process of achieving the goal of wideband releases three main-line models with different characteristics. The design process follows a log-periodic phase shifter theoretical analysis and optimization algorithm of the desired designing platform for circuit tuning. Three proposed main-line log-periodic phase shifters are short-circuited stub LPPS (SS-LPPS), double-sided LPPS (DS-LPPS), and Multilayer coupling LPPS (MC-LPPS). Compact size, planar, ease of fabrication, and wideband are the critical characteristics of the proposed structures. The broadband characteristic of the MC-LPPS is due to top and bottom Log-Periodic microstrip patches broadside coupling of 2 dB through an elliptical slot placed in a ground plane as a middle layer of a structure. Even-odd model analysis of design verification method employed. The optimized overall dimension of the final wideband proposed structure on the low-cost Rogers RO4003C substrate is 35 mm × 20 mm, Fabricated and tested. Experimental and simulation results have good agreement. S11 and S21 are better than −10 and − 1.45 dB in considered 141% fractional bandwidth (1.40-8.11 GHz) for a 130° continuous phase gradient, respectively.

Nonreciprocal Magnetoacoustic Waves in Dipolar-Coupled Ferromagnetic Bilayers

We study the interaction of surface acoustic waves (SAWs) with spin waves (SWs) in a ${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}$/$\mathrm{Au}$/${\mathrm{Ni}}_{81}{\mathrm{Fe}}_{19}$ system composed of two ferromagnetic layers separated by a nonmagnetic $\mathrm{Au}$ spacer layer. Because of interlayer magnetic dipolar coupling between the two ferromagnetic layers, a symmetric and an antisymmetric SW mode form, which both show a highly nondegenerate dispersion relation for oppositely propagating SWs. Due to magnetoacoustic SAW-SW interaction, we observe highly nonreciprocal SAW transmission in the piezoelectric-ferromagnetic hybrid device. We experimentally and theoretically characterize the magnetoacoustic wave propagation as a function of frequency, wave vector, and external magnetic field magnitude and orientation. Additionally, we demonstrate that the nonreciprocal SW dispersion of a coupled magnetic bilayer is highly tuneable and not limited to ultrathin magnetic films, in contrast to the nonreciprocity induced by the interfacial Dzyaloshinskii-Moriya interaction. Therefore, magnetoacoustic coupling in ferromagnetic multilayers provides a promising route towards building efficient acoustic isolators.

Physical fusion method of power grid information based on power flow calculation

From the perspective of information physical fusion, considering the relationship among power network, communication network and information network, the power information system model considering the coupling relationship between power network and information network is established. Firstly, a three-layer model framework of power information physical system considering communication transmission factors is proposed. The whole modeling process is divided into three parts: power network, information network and communication channel, which are effectively associated with power network and information network; Then, a mathematical model of power information physical system integration considering multi-layer coupling is proposed; Finally, the power information physical model based on ieee9 bus is used to verify the effectiveness of the proposed modeling method based on power flow calculation and topology analysis.

Enhancement of the spin-wave nonreciprocity in antiferromagnetically coupled multilayers with dipolar and interfacial Dzyaloshinskii-Moriya interactions

Spin-wave-based circuits and logic devices have been considered as an alternative to current electronic devices as they approach the physical limit of miniaturization. Asymmetrical propagation of spin waves, also known as nonreciprocity, provides an additional degree of freedom to these spin-wave-based devices, increasing their flexibility. In thin films, nonreciprocity can be induced by the Dzyaloshinskii-Moriya interaction (DMI) at heavy-metal/ferromagnet bilayers, and by the dipolar coupling in multilayers. Here, we show that in an antiferromagnetically coupled multilayer with interfacial DMI, the frequency nonreciprocity induced by the DMI is enhanced when both heavy metals are the same as long as the multilayer remains in an antiparallel state. Furthermore, we show that the interplay between the dipolar and Dzyaloshinskii-Moriya interaction enhances the nonreciprocity of one oscillation mode and reduces the nonreciprocity of the other. Which mode is enhanced depends on the sign of the induced Dzyaloshinskii-Moriya interaction at the interfaces and the magnetic moments of the layers. Finally, we show that it is possible to change the frequency nonreciprocity of Pt/Co/Cu/Co/Pt and Pt/Co/Cu/Py/Pt multilayers by $\ensuremath{\sim}7$ GHz when applying an in-plane magnetic field of 130 mT. This includes a change in the sign of the nonreciprocity, which could be used to control the direction of the flux of information in spin-wave devices.

Multi-layer coupling between SURFEX-TEB-v9.0 and Meso-NH-v5.3 for modelling the urban climate of high-rise cities

Abstract. Urban canopy models (UCMs) represent the exchange of momentum, heat, and moisture between cities and the atmosphere. Single-layer UCMs interact with the lowest atmospheric model level and are suited for low- to mid-rise cities, whereas multi-layer UCMs interact with multiple levels and can also be employed for high-rise cities. The present study describes the multi-layer coupling between the Town Energy Balance (TEB) UCM included in the Surface Externalisée (SURFEX) land surface model and the Meso-NH mesoscale atmospheric model. This is a step towards better high-resolution weather prediction for urban areas in the future and studies quantifying the impact of climate change adaptation measures in high-rise cities. The effect of the buildings on the wind is considered using a drag force and a production term in the prognostic equation for turbulent kinetic energy. The heat and moisture fluxes from the walls and the roofs to the atmosphere are released at the model levels intersecting these urban facets. No variety of building height at grid-point scale is considered to remain the consistency between the modification of the Meso-NH equations and the geometric assumptions of TEB. The multi-layer coupling is evaluated for the heterogeneous high-rise, high-density city of Hong Kong. It leads to a strong improvement of model results for near-surface air temperature and relative humidity, which is due to better consideration of the process of horizontal advection in the urban canopy layer. For wind speed, model results are improved on average by the multi-layer coupling but not for all stations. Future developments of the multi-layer SURFEX-TEB will focus on improving the calculation of radiative exchanges, which will allow a variety of building heights at grid-point scale to be taken into account.

Modeling Product Manufacturing Reliability with Quality Variations Centered on the Multilayered Coupling Operational Characteristics of Intelligent Manufacturing Systems.

For intelligent manufacturing systems, there are many deviations in operational characteristics, and the coupling effect of harmful operational characteristics leads to the variations in quality of the work-in-process (WIP) and the degradation of the reliability of the finished product, which is reflected as a loss of product manufacturing reliability. However, few studies on the modeling of product manufacturing reliability and mechanism analysis consider the operating mechanism and the coupling of characteristics. Thus, a novel modeling approach based on quality variations centered on the coupling of operational characteristics is proposed to analyze the formation mechanism of product manufacturing reliability. First, the PQR chain containing the co-effects among the manufacturing system performance (P), the manufacturing process quality (Q), and the product manufacturing reliability (R) is elaborated. The connotation of product manufacturing reliability is defined, multilayered operational characteristics are determined, and operational data are collected by smart sensors. Second, on the basis of the coupling effect in the PQR chain, a multilayered product quality variation model is proposed by mining operational characteristic data obtained from sensors. Third, an integrated product manufacturing reliability model is presented on the basis of the variation propagation mechanism of the multilayered product quality variation model. Finally, a camshaft manufacturing reliability analysis is conducted to verify the validity of the proposed method. The method proposed in this paper proved to be effective for evaluating and predicting the product reliability in the smart manufacturing process.