Elliptical Plane Research Articles

A Four Port Flexible UWB MIMO Antenna with Enhanced Isolation for Wearable Applications

This article presents a four-port multiple-input-multiple-output (MIMO) flexible antenna design for Ultrawideband (UWB) application using Polydimethylsiloxanes substrate. The single UWB antenna structure consists of modified circular radiator with elliptical slot and partial ground plane. To achieve high isolation among antenna element, a Defective Ground Structure (DGS) is adopted to decouple the low frequency band. DGS comprises a centrally placed square shape slotted structure connected by horizontal and vertical lines, achieving isolation below -20 dB. The proposed antenna has a dimension of , bandwidth of 3.4–11.8 GHz (110.5%) and 4.3 dBi peak gain. Simulation and measurement findings show that the antenna performs well under bending situations with different curvature radius. At 4 GHz and 8.1 GHz, W/kg specific absorption rate (SAR) for 1/10 g tissue is examined. A low value of SAR is obtained at both the resonating frequencies. Additionally, an analysis is conducted on the diversity parameters, and the antenna demonstrates comparatively good results having mean effective gain (MEG) ratio < -3 dB envelope correlation coefficient (ECC) < 0.02, total active reflection coefficient (TARC) < − 10 dB, channel capacity loss (CCL) < 0.3 bps/Hz, and diversity gain (DG) > 9.99 dB, implying that it's appropriate for wearable MIMO applications.

Investigation on two-dimensional ultrasonic vibration plane turning method based on elliptical plane swinging strategy along short axis

In the ultrasonic elliptical vibration cutting (UEVC) process, the surface morphology suffers from the large fluctuation of ridge height and residual height, which has restricted the development of UEVC technology. Therefore, on the basis of the elliptical plane swinging strategy along a short axis, a surface topography improvement method (i.e., swing ultrasonic elliptical vibration turning (SUEVT)) for two-dimensional ultrasonic vibration plane turning is proposed in this study. The core idea of the method is to swing the ultrasonic elliptical vibration plane along the short axis to form a machining inclination angle, which reduces the ridge height of the machined morphology to a certain extent, thereby optimizing the surface microstructure and reducing the surface roughness. First, this study establishes a mathematical model of the tool tip trajectory of ultrasonic elliptical vibration under different swing angles, theoretically analyzes the influence of swing angles on the tool tip trajectory and surface topography, and provides a theoretical basis for revealing the surface topography formation mechanism of SUEVT. Second, an engineering practice scheme of SUEVT is proposed, and a processing experiment platform is built. Finally, cutting experiments of SUEVT for TC4 titanium alloy were conducted, studying the influence of swing angles on surface topography and roughness and assessing the feasibility of the method. Results showed that compared with ultrasonic elliptical vibration turning (UEVT), SUEVT has certain advantages in improving surface morphology. When the swing angle of SUEVT is 15°, the surface roughness decreases the most, reaching 19.00 %. Under the condition of SUEVT θ = 15°, the surface roughness decreases first and then increases with the increase in spindle speed, while it is proportional to the feed speed and ultrasonic power. The method proposed in this study can provide new methods and new ideas for ultrasonic elliptical vibration high surface quality machining.

Planar Hall Effect Magnetic Sensors with Extended Field Range.

The magnetic field range in which a magnetic sensor operates is an important consideration for many applications. Elliptical planar Hall effect (EPHE) sensors exhibit outstanding equivalent magnetic noise (EMN) on the order of pT/Hz, which makes them promising for many applications. Unfortunately, the current field range in which EPHE sensors with pT/Hz EMN can operate is sub-mT, which limits their potential use. Here, we fabricate EPHE sensors with an increased field range and measure their EMN. The larger field range is obtained by increasing the uniaxial shape-induced anisotropy parallel to the long axis of the ellipse. We present measurements of EPHE sensors with magnetic anisotropy which ranges between 12 Oe and 120 Oe and show that their EMN at 10 Hz changes from 800 pT/Hz to 56 nT/Hz. Furthermore, we show that the EPHE sensors behave effectively as single magnetic domains with negligible hysteresis. We discuss the potential use of EPHE sensors with extended field range and compare them with sensors that are widely used in such applications.

Flexible planar Hall effect sensor with sub-200 pT resolution

Flexible sensors are important for applications, such as wearable medical devices, soft robotics, and more, as they can easily conform to soft and irregularly shaped surfaces. This study presents elliptical planar Hall effect magnetic sensors fabricated on a polyamide tape with an equivalent magnetic noise (EMN) better than 200 pT/Hz. The sensor is characterized in flat and bent states with a bent radius of 10 mm. An EMN of 200 and 400 pT/Hz in flat and bent states, respectively, is achieved at a frequency of 100 Hz. The remarkable EMN combined with a simple, low-cost fabrication process makes these sensors a promising candidate for flexible electronics.

A Runge theorem for generalized analytic functions

AbstractWe show an approximation theorem of Runge type for solutions of the generalized Vekua equation , where L belongs to a class of degenerate elliptic planar vector fields and . To prove the theorem, we make use of an integral representation for the solutions of the generalized Vekua equation valid on relatively compact sets. As an application, we study the global solvability of the equation with and some of its consequences.

Theoretical research on the transverse spin of structured optical fields inside a waveguide

Structured optical fields inside a waveguide possess the transverse spin, i.e., the spin angular momentum perpendicular to the direction of the waveguide. The physical origin of the transverse spin can be attributed to the presence of an effective rest mass of photons in guided waves, or equivalently, to the existence of a longitudinal field component, such that the transverse and longitudinal fields together form an elliptical polarization plane. In contrary to the traditional viewpoint, the transverse spin of photons in guided waves is also quantized, and its quantization form is related to the ellipticity of the polarization ellipse. The direction of the transverse spin depends on the propagation direction of electromagnetic waves along the waveguide, such a spin-momentum locking may have important applications in spin-dependent unidirectional optical interfaces. By means of a coupling between the transverse spin of guided waves and some physical degrees of freedom, one can develop an optical analogy of spintronics, i.e., spinoptics.

Planar Elliptical Inductor Design for Wireless Implantable Medical Devices

Wireless implantable medical devices (WIMDs) have seen unprecedented progress in the past three decades. WIMDs help clinicians in better-understanding diseases and enhance medical treatment by allowing for remote data collection and delivering tailored patient care. The wireless connectivity range between the external reader and the implanted device is considered one of the key design parameters in WIMD technology. One of the common modes of communication in battery-free WIMDs is inductive coupling, where the power and data between the reader and the implanted device are transmitted via magnetically coupled inductors. The design and shape of these inductors depend on the requirements of the application. Several studies have reported models of standard planar inductors such as circular, square, hexagonal, and octagonal in medical applications. However, for applications, constrained by narrow implantable locations, elliptical planar inductors may perform better than standard-shaped planar inductors. The aim of this study is to develop a numerical model for elliptical inductors. This model allows for the calculation of the inductance of the elliptical planar inductor and its parasitic components, which are key design parameters for the development of WIMDs powered by inductive coupling. An area transformation technique is used to transform and derive elliptical inductor formulas from standard circular inductor formulas. The proposed model is validated for various combinations of the number of turns, trace width, trace separation, and different inner and outer diameters of the elliptical planar inductor. For a thorough experimental validation of the proposed numerical model, more than 75 elliptical planar inductors were fabricated, measured, and compared with the numerical output of the proposed model. The mean error between the measured inductor parameters and numerical estimates using the proposed model is <5%, with a standard deviation of <3.18%. The proposed model provides an accurate analytical method for estimating and optimizing elliptical planar inductor parameters using a combination of current sheet expression and area transformation techniques. An elliptical planar inductor integrated with a sensing element can be used as a wireless implant to monitor the physiological signal from narrow implantation sites.

High Sensitivity Planar Hall Effect Magnetic Field Gradiometer for Measurements in Millimeter Scale Environments.

We report a specially designed magnetic field gradiometer based on a single elliptical planar Hall effect (PHE) sensor, which allows measuring magnetic field at nine different positions in a 4 mm length scale. The gradiometer detects magnetic field gradients with equivalent gradient magnetic noises of ∼958, ∼192, ∼51, and ∼26 nT/m√ Hz (pT/mm√Hz) at 0.1, 1, 10, and 50 Hz, respectively. The performance of the gradiometer is tested in ambient conditions by measuring the field gradient induced by electric currents driven in a long straight wire. This gradiometer is expected to be highly useful for the measurement of magnetic field gradients in confined areas for its small footprint, low noise, scalability, simple design, and low costs.

The static and free vibration analyses of axially functionally graded elliptical beams via mixed FEM

The objective of this study is to investigate the behavior of the static and free vibration analyses of axially functionally graded elliptical planar curved beams using a mixed finite element method (MFEM) based on the Timoshenko beam theory. A two-noded curved mixed finite element has 12 field variables at each node. These variables denote three displacements, three cross-sectional rotations, three forces, two bending moments, and torque, respectively. The functionally graded material is composed of ceramic-particle material and metal-matrix material. The volume fraction of ceramic and metal materials varies along the beam axis. The effective material properties (modulus of elasticity, Poisson's ratio, and density) of the functionally graded material are determined according to the rule of mixture. It is aimed in the benchmark examples to present the influence of ceramic-particle material and non-homogeneity index of material gradation, the minimum radius of the elliptical beam, and boundary condition to the results of static and free vibration analysis in detail.

Efficacy of Transosseous Tunnel Placement for Triple Endobutton Plate in Acromioclavicular Joint Reconstruction: A Three-Dimensional Printing Guide Design Technology.

ObjectiveExplore an accurate transosseous tunnel drilling method based on three‐dimensional (3D) printing technology for acromioclavicular joint reconstruction (ACD), design a guide design, and evaluate its accuracy.MethodsUsing Mimics software to reconstruct 100 cases of acromioclavicular joint computed tomography (CT) data. In design 2, the non‐collinear tunnel is superimposed on the 3D model, and a virtual drilling is performed between the clavicle and the coracoid using a triple inner gusset. Then, in the Geomagic Studio software model, an elliptical plane is calculated and extracted as a guide design for precise drilling. Then put the design and the 3D shoulder model together for 3D printing. Ten lengths were measured, and the effects of the virtual model, the actual model, and the guide rail design were compared.ResultsWe successfully compared 10 parameters of 3D virtual model and actual model. There was no significant difference between actual and virtual bone tunnels in 10 measurements (P > 0.05).ConclusionsThe accuracy of ACD combined with 3D printing guidance design technology in the transosseous tunnel of adult shoulder is reliable.

Extending the horizontal transmission range of an inductive wireless power transfer system using passive elliptical resonators

This paper investigates the development of a passive elliptical planar coil for extending the horizontal transmission distance in an inductive transmitter-receiver wireless-power transfer system (WPT). The passive base coil partially overlaps the transmitter coil and extends the horizontal wireless link between the transmitter and receiver. The base coil models investigated are divided into three categories based on their length. Moreover, for each length category, the optimum number of turns is determined. All proposed models are analysed through the electromagnetic simulation (EMF) software Ansys–Maxwell and Simplorer as well as validated experimentally. For the entire analysis, the maximum efficiency principle is followed in this system. Therefore, impedance matching networks are used across all three terminals in order to tune the system to the operating frequency of 200 kHz to achieve maximum efficiency. The maximum achievable efficiency is determined for each coil prototype (in both simulation and experiment) and the results are compared. The extent to which the EMF software is a valuable tool in developing a planar passive base for an inductive WPT system is discussed. Overall, the proposed concept behind the passive base coil is proved to be successful in extending the horizontal distance between the transmitter and receiver.

Measurements of nanomagnetic bead relaxation dynamics using planar Hall effect magnetometer

We study the magnetization dynamics of nanomagnetic beads with a diameter ranging from 80 to 250 nm in frequency and time domains using a high-resolution elliptical planar Hall effect (EPHE) sensor integrated with a fluidic channel. We find that the dynamics are well described with Cole–Cole and exponential decay models for frequency and time domains, respectively. We discuss the potential use of EPHE sensors in lab-on-a-chip applications.

Rapid fabrication technique for aluminum optics by inducing a MRF contamination layer modification with Ar+ ion beam sputtering.

Aluminum optics are widely used in modern optical systems because of high specific stiffness and high reflectance. Magnetorheological finishing (MRF) provides a highly deterministic technology for high precision aluminum optics fabrication. However, the contamination layer will generate on the surface and bring difficulties for the subsequent processes, which highly limit the fabrication efficiency and precision. In this study, characteristics of the contamination layer and its formation process are firstly revealed through experimental and theoretical methods. Impurities such as abrasives are embedded into the aluminum substrate causing increasing surface hardness. The influence of the contaminant layer on machining accuracy and machining efficiency is analyzed in this study. Based on the analysis, ion beam sputtering (IBS) is induced as a contamination layer modification method. Impurities will be preferential sputtered during the process. Surface hardness and brightness will restore to the state before MRF. Moreover, the thickness of the contamination layer reduces dynamically during IBS because of the bombardment-induced Gibbsian segregation and sputter yield amplification mechanism. Consequently, we proposed a combined technique that includes MRF, IBS and smoothing polishing. Comparative experiments are performed on an elliptical shape plane surface. The results indicate that the efficiency has been increased sevenfold and surface precision is also highly improved. Our research will promote the application of aluminum optics to the visible and even ultraviolet band.

RETRACTED ARTICLE: A Novel Eye-Shaped Monopole Antenna for Dual Band and Wideband Communication Applications

This paper presents a compact dual-band monopole antenna printed on the low-cost FR4 substrate for multi wireless communication applications. The novel antenna consists of an eye-shaped patch and a semi-circular shaped slot on the half elliptical ground plane. The combination of the eye-shaped patch and a semi-circular shaped slot on the ground is used to expand the total length of the current path. This expansion improved the return loss and broadened the bandwidth of the two bands for the desired antenna. The antenna’s measurement results include multi-band frequencies such as S, C, X, Ku, K and Ka-band which covers the bandwidth requirements of WiMAX, WLAN, satellite TV, and other applications at the lower and upper-frequency band. The dimension of the antenna is (26 × 20 × 1.6) mm3 at the minimum frequency of 3.15 GHz. The proposed configuration operates at 3.55 and 19.95 GHz with a bandwidth of about 28.17% (3.15–4.15 GHz), and 147.37% (5.25–34.65 GHz), respectively for the simulation part. The measured bandwidth (− 10 dB) for S11 in the lower and upper band is about 49.71% (2.688–4.506 GHz) and 152.01% (4.933–35.861 GHz) at a center frequency of 3.657, and 20.346 GHz, respectively. The proposed antenna has a suitable radiation characteristic of 97% and 91% and a good gain of 2.97 dBi and 6.71 dBi, at the lower and upper operating band. The Vector Network Analyzer (VNA) Rhode & Schwarz ZVA40 device has been used to measure the results of the antenna and both of the software ANSYS-electromagnetic suite and CST microwave studio is used to simulate the results of the design.

Thickness dependence of elliptical planar Hall effect magnetometers

We fabricate elliptical planar Hall effect magnetometers with Permalloy thickness ranging between 25 and 200 nm. We study the thickness dependence of their equivalent magnetic noise by examining the effect of the layer thickness on the signal and noise including Joule heating contributions. Sensors with a thickness of 50 nm achieve equivalent magnetic noise as low as ∼24 pT/√ Hz at 50 Hz and ∼36 pT/√ Hz at 10 Hz, which are the best reported values for any type of magnetic sensor of similar or smaller size. These results are achieved without the use of magnetic flux concentrators, which helps to reduce the sensor volume while improving its spatial resolution and reducing the complexity and time of its production and, hence, its potential cost. We discuss different routes for further resolution improvements.

A Novel Eye-shaped Monopole Antenna for Wideband and 5G Applications

ABSTRACT This paper presents a compact dual-band monopole antenna printed on the low-cost FR4 substrate for multi wireless communication applications. The novel antenna consists of an eye-shaped patch and a semicircular shaped slot on the half elliptical ground plane. The antenna’s measurement results include multiband frequencies such as S, C, X, Ku, K, and Ka-band, which covers the bandwidth requirements of WiMAX, WLAN, satellite TV, and 5G applications at the lower and upper-frequency band. The dimension of the antenna is (26 × 20 × 1.6) mm3 at the minimum frequency of 3.15 GHz. The proposed configuration operates at 3.55 and 19.95 GHz with a bandwidth of about 28.17% (3.15–4.15 GHz) and 147.37% (5.25–34.65 GHz), respectively, for the simulation part. The measured bandwidth (−10 dB) for S11 in the lower and upper band is about 49.71% (2.688–4.506 GHz) and 152.01% (4.933–35.861 GHz) at a centre frequency of 3.657 and 20.346 GHz, respectively. The proposed antenna has a stability of the radiation characteristics, suitable gain, and good impedance across the operating bandwidth of the dual-band antenna.

Ancient shapes for modern architectural and acoustic design: Large interiors formed by curved surfaces

Ancient architectural shapes as domes and other curved surfaces are widely admired by architects even if they may present serious acoustical hazards. In large interiors formed by curved surfaces, acoustical singularities such as the “sliding” of sound along a concave wall or a concentration of sound in a distant location of the room may happen. These phenomena can be mostly found in historical spaces where these effects were usually detected accidentally creating an atmosphere of mystery. Nowadays, in contemporary auditoriums they are mostly considered an acoustic flaw and they must be corrected or eliminated. A practice in avoiding these miraculous acoustical properties, the focusing and whispering, is not usually applied and other shapes are preferred for new projects.In the paper architectural acoustic design approaches and solutions to maintain ancient shapes for modern architectural and acoustic design are investigated. A geometrical acoustic analysis is presented, followed by the description of different methods for avoiding focusing and whispering applied to a case study.Room Acoustics procedures and implementations of computer simulation techniques are included. A procedure for acoustic design for spaces with circular and elliptical plane or/and sections is suggested where the acoustic response is suitable for multipurpose uses.

Feather-shaped super wideband MIMO antenna

AbstractTwo configurations of a modified feather-shaped antenna element are proposed for super wideband (SWB) multiple-input multiple-output (MIMO) applications. The antenna element geometry comprises of a circular slot-loaded feather-shaped radiator and rectangular notch-loaded quarter elliptical coplanar waveguide ground plane. An operating bandwidth of 4.4–51.5 GHz with inter-port isolation, S21 ≥ 15 dB for spatial diversity configuration, and 3.8–51.5 GHz with S21 ≥ 15 dB in pattern diversity configuration are achieved. The footprints of the antenna configurations are 17 × 33 and 31 × 31 mm2. Both configurations exhibited an envelope correlation coefficient of &lt;−20 dB. The proposed MIMO configurations are fabricated and experimentally validated. The designed antenna configurations are SWB and compact.

Expert Opinion Dimensions of Rural Landscape Quality in Xiangxi, Hunan, China: Principal Component Analysis and Factor Analysis

Scholars and planning/design professionals are interested in the quantitative, metric properties influencing the quality and assessment of rural landscape space. These metrics are important for guiding rural planning, design, and construction of cultural rural environments. Respondents and metrics from four sampled villages (Qixin, Hangsha, Yanpai Xi, and Lvdong) in the Xiangxi District of Hunan Province in China were examined, employing statistical principal component analysis and factor analysis methods to understand the identifying properties concerning planning and design features of these rural mountain village landscape spaces. The two approaches reveal different aspects from the same variables. Through factor analysis and rotation, four general dimensions were revealed explaining approximately 62% of the variance: a settlement and environmental axis, an intangible culture axis, a productive landscape axis, and a transportation and public space axis, supporting the standing notion that the variables were ordinated across four dimensions in these mountain villages and occupied an elliptical plane that was different than the predicted space occupied by nearby cites. In contrast, principal component analysis revealed that the variables could be grouped into one latent dimension explaining 48% of the variance and revealing an alternative interpretation and spatial plot of the sites.

Describing the Asymptotic Behavior of a Low-Viscosity Fluid in an Elliptical Plane with a Moving Boundary

A problem of plane-parallel steady motion of a low-viscosity incompressible fluid inside an elliptical cavity with a wall moving along its contour is under consideration. A slip condition with a constant or piecewise-constant slip function is set at the cavity boundary. This problem is solved using the method of merging asymptotic expansions. When the Reynolds number is of the order of Re = 1500 and there are no corner points in the flow region, the calculation time decreases by hundreds of times compared with the case where the finite difference method is applied. The flow region is divided into an inviscid core in which vorticity is constant and a “weak” boundary layer. The equation of the “weak” boundary layer by changing variables is reduced to a heat equation whose solution is constructed in the form of a series.