Elliptical Patch Research Articles

Reconfigurable leaky wave antenna with low sidelobe based on spoof surface plasmon polariton

A low sidelobe leaky wave antenna (LWA) based on Spoof Surface Plasmon Polariton (SSPP) with switchable right/left-handed circular polarization (CP) and linear polarization (LP) radiation function by controlling the status of two PIN diodes is proposed. Two symmetrical SSPP transmission lines (TLs) are connected through two PIN diodes, and the ON–OFF of diodes constitute three different transmission modes. Two rows of the tapered arranged elliptical patches are loaded periodically around the TL to break the original stable transmission structure for radiation, and suppress the antenna sidelobe levels to less than −10 dB. After experimental verification, the reconfigurable antenna can reach three functionalities: (1) Mode 1: 22°right-handed CP beam scanning from 8.3 to 9.0 GHz; (2) Mode 2: 22°left-handed CP beam scanning from 8.3 to 9.0 GHz; (3) Mode 3: 78°LP beam scanning from 8.3 to 10.3 GHz. In Mode 1 and 2, the axial ratios (ARs) are lower than 3 dB, and the average gain can reach 11.6 dBi, while 13.4 dBi in Mode 3. A leaky wave antenna that can switch the radiation function of linear/circular polarization with favorable performance characteristics, such as wide scanning range, high gain, low sidelobe levels, and high efficiency, makes it an ideal candidate for wireless communication.

A conical-beam dual-band double aperture-coupled stacked elliptical patch antenna design for 5G

This study investigates a dual-band, aperture coupled and stacked elliptical patch antenna with conical radiation. To obtain such characteristics, the TM21 mode of the radiating elliptical patches is excited by utilizing two special apertures and shorting planes. The proposed antenna operates both at 2.45 GHz and 3.5 GHz. The design aims to be used indoor applications of 5G operating in both free and planned 5G bands, respectively. Therefore, the low-profile antenna element that has a monopole-like radiation pattern is a good candidate for two-dimensional arraying. The design steps and the evolution of the proposed antenna are presented in detail. The simulation and experimental results reveal many similarities regarding the scattering parameters, radiation patterns, and gain. The scattering parameter, S11 is less than -10 dB in both operating bands. Novelties of the proposed study are the configuration and choice of the apertures as well as stacking structure and miniaturization techniques in elliptical patches.

Generalisation of the linear theory of rolling contact to a single double-elliptic contact region and its application to solve non-Hertzian contact problems using extended FASTSIM

Most contact models addressing the solution of the tangential problem assume an elliptical shape of the contact patch which is derived from the Hertz theory. In particular, the linear theory of rolling contact developed by Kalker is based on this assumption. However, it is well known that in many practical cases the shape of the contact region formed between the rail and a railway wheel can be far from elliptic. Recently, the Simple Double-Elliptic Contact (SDEC) shape has been proposed as an approximation of a wide variety of non-elliptic patches. In this paper, a formulation of the linear theory of rolling contact for a SDEC shape is proposed. The coefficients of the original linear theory for elliptic patches are maintained and four new coefficients are introduced to consider the effect of non-ellipticity. The coefficients of the theory are derived numerically using software CONTACT. Then, an extension of FASTSIM for a SDEC region is introduced and the obtained creep force curves under various conditions are compared to existing formulations of FASTSIM, using results from software CONTACT as a reference. The comparisons show that the proposed model is as fast as FASTSIM and provides more accurate solutions than existing versions of FASTSIM.

Model Construction, Theoretical Analysis, and Miniaturized Implementation of High-Order Deflected Multivortex Beams With Uniform Elliptical Array

This work proposes a miniaturized uniform elliptical array (UEA) to generate high-order multivortex beams with mixed orbital angular momentum (OAM) modes in different directions. First, the construction method of the UEA model is proposed, and different miniaturized UEA models are designed to generate multivortex beams. On this basis, the UEA and uniform circular array (UCA) models are compared, and the modified radiation pattern product theorem is proposed to design high-order deflected vortex beams with fewer elements. Then, a miniaturized elliptical ring patch antenna is analyzed according to the theory of characteristic modes at 5.8 GHz. Finally, a miniaturized UEA is constructed by the miniaturized patch antennas under the guidance of the proposed UEA model and the modified radiation pattern product theorem. The UEA with four elements and corresponding feed networks generates four vortex beams with different directions and mixed modes, including the OAM modes of ±2. The designed device can generate high-order deflected multivortex beams by significantly reducing the number of elements to reduce system complexity and cost. The vortex beams with different directions and mixed modes expand the coverage of the vortex beams and provide the possibility for high-capacity OAM radio frequency communication.

An extended LuGre-brush tyre model for large camber angles and turning speeds

ABSTRACT This paper presents a novel tyre model which combines the LuGre formulation with the exact brush theory recently developed by the authors, and which accounts for large camber angles and turning speeds. Closed-form solutions for the frictional state at the tyre-road interface are provided for the case of constant slip inputs, considering rectangular and elliptical contact patches. The steady-state tyre characteristics resulting from the proposed approach are compared to those obtained by employing the standard formulation of the LuGre-brush tyre models and the exact brush theory for large camber angles. Then, to cope with the general situation of time-varying slips and spins, two approximated lumped models are developed that describe the aggregate dynamics of the tyre forces and moment. In particular, it is found that the transient evolution of the tangential forces may be approximated by a system of two coupled ordinary differential equations (ODEs), whilst the dynamics of the self-aligning moment may be described by combining two systems of two coupled ODEs. Given its stability properties and ease of implementation, the lumped one may be effectively employed for vehicle state estimation and control purposes.

A Circular Polarization-Reconfigurable Antenna With Enhanced Axial Ratio Bandwidth

Acircular polarization (CP)-reconfigurable antenna array with enhanced axial ratio (AR) bandwidth and high gain is proposed in this letter. By loading the tuning resistor on the annular coupling slot, the AR bandwidth of the initial design is significantly improved. Furthermore, the elliptical grid-slit patch is employed to mitigate the decreased AR performance caused by the parasitic effect from PIN diode switches while improving the gain. A prototype of a 2×2 array is developed, fabricated, and measured. Experiments show that the AR bandwidth is 31.6%, while the measured peak gain is up to 16.3 dBic.

Fractal loaded six element multiple‐input‐multiple‐output antenna configuration for super wideband operation

In this article, a planar six port multiple-input-multiple-output (MIMO) antenna configuration, fabricated on 80 × 120 mm2 FR4 substrate has been presented for super wideband (SWB) operation. The different co-planar waveguide (CPW) fed antenna elements are placed in side by side, perpendicular and upside down arrangements among themselves. A combination of Minkowski and modified Hilbert fractal curve has been applied on half elliptical patch antenna elements. Two pairs of antenna elements operate from 1.2 to 20 GHz and the other pair of antenna elements covers a bandwidth ranging from 1.4 to 20 GHz. Due to the utilization of different metallic stubs, fractal curves and proper positioning of the antenna elements, inter-element isolation more than 20 dB is achieved over the whole frequency band. The proposed design also exhibits suitable radiation characteristics with enough gain and better diversity performance parameters. The time-domain analysis of the proposed design in terms of group delay also confirms its application as a good SWB MIMO antenna configuration.

Elliptical Patch Microstrip Antenna for Bluetooth/Wi-Fi Applications

In the wireless communication applications, widespread usage of microstrip patch antennas due to their advantages such as compactness, easy fabrication and low cost, is pushed forward researchers to develop desired antennas or improve the existing antennas to get desired one. But it is challenging to get desired antennas since microstrip patch antennas have some disadvantages such as low gain and narrow bandwidth. In this work, elliptical patch microstrip antenna is designed for Bluetooth/Wi-Fi applications. The antenna is designed in the form of slotted elliptical patch and defected ground structure method. Defected ground structure method is applied by using rectangular slots with different dimensions in this work. The proposed antenna is modelled using CST MWS software. Return loss, gain and directivity values are -16.45 dB, 1.82 dBi, and 5.81 dBi at 2.45 GHz, respectively. On the other hand, maximum directivity and gain values are 5.86 dBi and 2.06 dBi at 2.4 GHz, respectively. The bandwidth is 63.1 MHz (2.41 GHz – 2.48 GHz) at 2.45 GHz. According to the results, IEEE 802.11 b/g standards are supported by the designed antenna. So, it can be used for Bluetooth and Wi-Fi applications at 2.4 GHz.

Ultrawide-Angle and High-Scanning-Rate Leaky Wave Antenna Based on Spoof Surface Plasmon Polaritons

An ultrawide-angle frequency beam scanning leaky-wave antenna (LWA) with a high scanning rate based on spoof surface plasmon polaritons (SSPPs) waveguide is proposed in this communication. A row of elliptical patches is placed periodically near the SSPPs waveguide, which can shift the fundamental mode of SSPPs waveguide to the fast-wave region and radiate electromagnetic (EM) waves. The simulated results show that the proposed LWA achieves an ultrawide scanning angle range of 172° over a narrow operation bandwidth of 9.8–12.28 GHz, which implies a high scanning rate. The simulated average gain of the proposed LWA is 10.13 dBi and its average total efficiency is 75.35%. The proposed LWA is fabricated and measured. The measured scanning angle range is 167° in the frequency band of 9.9–12.25 GHz, and the measured average gain is 9.73 dBi. Good agreements between the simulated and measured results are obtained, validating the proposed design.

Different Feeding Techniques of Elliptical Patch Antenna at X Band for Radar Applications

Different Feeding Techniques of Elliptical Patch Antenna at X Band for Radar Applications

Design of circularly polarized flat‐top pattern with phase gradient metasurface

This article presents a metasurface (MTS) for designing a circular polarized (CP) flat-top radiation pattern using the phase compensation method. The basic idea is to generate multiple beams pointing in different directions by dividing the entire MTS into sub-regions. The MTS consists of four-layered elliptical patches encircled in a square loop printed on three dielectric substrates. The asymmetric nature of the unitcell produces two orthogonal components with equal magnitude and 90° phase difference to obtain the required linear to circular polarization conversion. The proposed MTS consists of 15 × 15 unitcells, and is fed by a rectangular patch antenna operating at 10 GHz. The flat-top pattern has been observed in the 3-D plane for u,v-polarized wave incidences at 9.9 GHz. For u-polarized incidence wave results in left-hand circular polarized (LHCP) flat-top radiation pattern with a 1 dB beamwidth of 37.5°. The axial ratio is less than 3 dB in all planes within the 1-dB beamwidth at 9.9 GHz. Similarly, for v-polarized incident wave, identical characteristics have been observed for right-hand circular polarization (RHCP), which enables the proposed structure for polarization diversity.

Super UWB Grooved and Corrugated Antenna for GPR Application

A novel super Ultra-Wideband (UWB) monopole antenna for Ground Penetrating Radar (GPR) application is investigated in this paper. The designed antenna is constructed by a grooved elliptical patch and a corrugated semi-elliptical ground plane. The designed antenna is fabricated on the FR4-substrate that has a compact size of 0.195 λ0 × 0.1625 λ0 × 0.00975 λ0 at 1.95 GHz. The measurements are performed by using a well calibrated R&S®ZNB Vector Network Analyzer. The measured results show that the fabricated prototype covers a super UWB extending from 1.95 GHz to upper than 20 GHz (>164.46 %). Additionally, the voltage standing wave ratio (VSWR) and the gain responses of the antenna are simulated in close proximity to a dry/wet sand box to verify the penetration ability of the antenna. The results are acceptable which guarantee the aptitude of this antenna to operate as a GPR antenna.

On Design of a Triple Elliptical Super Wideband Antenna for 5G Applications

A novel compact triple elliptical monopole antenna has been designed, analyzed and fabricated for super wideband applications. To enhance the impedance bandwidth, the author proposed a monopole antenna with a triple elliptical patch excited by a 50Ω triangular tapered microstrip feedline. Further improvement is achieved by optimally modifying the Defected Ground Structure (DGS) of the antenna. The proposed patch structure is mounted on a Roger’s RT-Duroid 5880 substrate (ϵ_r= 2.2, tan δ = 0.0009) and has compact physical dimensions of 27 mm × 29.5 mm. The fabricated antenna covers the frequency band from 1.91 GHz to 43.5 GHz for S₁₁ ≤ -10 dB with a fractional bandwidth of >183.17% and has a ratio bandwidth of 22.77:1. This extended bandwidth coverage permits the antenna to operate for wide range of application including 5G and Internet of Things (IoT). The proposed antenna has a very Bandwidth Dimension Ratio (BDR) of 5761.87 which makes it the best candidate for superwideband antenna. Far field measurements disclose an omnidirectional radiation pattern across the frequency of operation. Further, the farfield Radar Cross Section (RCS) is analyzed through simulation and it is to be noted that relatively low values are obtained through out the frequency of operation. In addition, the compactness of the proposed antenna is theoretically verified with the aid of fundamental dimension limit theorem.

A simple and effective broadband decoupling structure for UWB-MIMO antenna

Abstract A new type of closed square ring decoupling structure is proposed in this letter, which can effectively reduce the coupling of antennas. The designed antenna is composed of two elliptical monopoles and a common ground loaded with a broadband parasitic decoupling structure. Considering the impedance matching, each antenna element is changed from the original rectangular microstrip feed to a tapered microstrip feed and etched a circular slot on the elliptical monopole patch. By comparison with the original antenna without any decoupling structure, through loading the broadband decoupling structure on the ground, the antenna isolation is improved by 10 dB in most frequency bands. Comparing simulation and measurement results, the antenna achieves better than 25 dB isolation over the whole operating band (3.3–12 GHz). By manufacturing and testing the antenna designed in this article, the excellent performance parameters obtained also prove that the antenna can be used in portable devices.

Elliptical Slot Microstrip Patch Antenna Design Based on a Dynamic Constrained Multiobjective Optimization Evolutionary Algorithm

Most evolutionary optimization algorithms have already been used for antenna design and shown promising results on improving the performance of the antenna. However, for many real-world antenna optimization problems, they are difficult to solve in that there are highly constrained and multimodal difficulty. These difficulties impede the development of antenna design. In this paper, an elliptical slot microstrip patch antenna design with these difficulties is modeled as a constrained optimization problem (COP). To address the problem, a Dynamic Constrained Multiobjective Optimization Evolutionary Algorithm(DCMOEA) is used. The experimental results show that the optimum antenna with satisfying the design requirement is obtained, and as well as we find the radiation patch should be a whole ellipse instead of subtracting with two ellipses.

Infinite length slotted ultra-wideband monopole antenna using step-feed with band notch characteristics

AbstractIn this work, a printed ultra-wideband (UWB) antenna has been proposed exhibiting band notch characteristics. The proposed design covers the entire UWB band except for the 3.5 GHz band providing the band notch for the WiMAX band. This design consists of two-quarter elliptical patches placed symmetrically over the FR4 substrate. The elliptical shape of the patch is responsible for the UWB band achieved. The slot has been created on the optimized patch area to achieve the desired characteristics providing a notch for the WiMAX band. The slot in the patch is so perfectly designed that it gives the patch a perfect shape of butterfly wings. After designing, the proposed antenna was simulated and then fabricated. The fabricated and simulated results are in close agreement with each other which shows, the proposed UWB antenna is good enough for biomedical applications.

Study of rail-wheel contact problem by analytical and numerical approaches

This study presents the rail wheel contact problems under normal and tangential categories. Both analytical and numerical approaches were used for modelling, where the analytical approach assumed elliptical contact patches based on the Hertz theory. In the numerical approach, 3D finite element models were used to investigate non-elliptical contact patches. The only elastic material model was considered in the case of Hertz theory. However, in the case of finite element analysis, both elastic and elastoplastic material models were used to simulate the material's behavior under the applied load. The elastoplastic material model was used to determine the amount of stress at which the plastic deformation starts, which enables determining the rail wheel's critical load. The commercial software ABAQUS was employed for 3D modeling and contact stress analysis. The study shows maximum stress at 3 mm from the rail wheel contact surface when the maximum load of 85 kN is applied. This initiates the cracks in the subsurface and causes the portion of the rail wheel to break off in the form of spalling after a certain time.

Elliptical Slot Microstrip Patch Antenna Design Based on a Dynamic Constrained Multiobjective Optimization Evolutionary Algorithm

Most evolutionary optimization algorithms have already been used for antenna design and shown promising results on improving the performance of the antenna. However, for many real-world antenna optimization problems, they are difficult to solve in that there are highly constrained and multimodal difficulty. These difficulties impede the development of antenna design. In this paper, an elliptical slot microstrip patch antenna design with these difficulties is modeled as a constrained optimization problem (COP). To address the problem, a Dynamic Constrained Multiobjective Optimization Evolutionary Algorithm(DCMOEA) is used. The experimental results show that the optimum antenna with satisfying the design requirement is obtained, and as well as we find the radiation patch should be a whole ellipse instead of subtracting with two ellipses.

Low-Profile, Broadband, Dual-Linearly Polarized, and Wide-Angle Millimeter-Wave Antenna Arrays for Ka-Band 5G Applications

A low-profile, broadband, dual-linearly polarized (dual-LP), and wide-angle millimeter-wave antenna array with beam-steerable capabilities operating in the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ka</i> -band is proposed for 5G applications. By jointly exploiting miniaturized vertically stacked elliptical patches, orthogonal aperture-coupled stripline feeding structures, and groups of shorting pins loaded close to the coupling apertures, the proposed dual-LP element has a small footprint of 4.5 × 4.5 mm with a total thickness of 1.57 mm, which exhibits a measured −10 dB impedance bandwidth of 21.8% and a mutual coupling below −41 dB. Wideband stripline-based Butler matrix circuits are designed and integrated with the 1 × 4 element array for verifying its broadband dual-LP multibeam radiation performance. Experimentally, the integrated array generates four beams with an angular coverage of about ±61° and ±75° for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> - and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -polarizations, revealing that the proposed array is a promising candidate for 5G applications.

DESIGN OF ULTRA-WIDEBAND ANTENNA WITH NOTCHED BANDS TO REJECTING UNWANTED BANDWIDTH

Design of Ultra-Wideband ring patch antenna with a band notch is presented in this study. The elliptical antenna is modified to Ultra-wideband at a range (3.1-10.6) GHz using a Microstrip patch antenna with the feedline impedance 50 ohm and rectangular each side of the elliptical patch has a slot. The dimensions optimized by the sweep parameter for the proposed antenna are (40 x 40 x 1.6) mm3 to provide a band notch and remove the (3.1–3.7 GHz) WiMAX band and (7.1 GHz) X-band, a rectangular-shaped slot etched on the patch is used. Inserting slots changing the current distribution is used in the patch to control the band notches. The results demonstrate that the suggested X-band and WiMAX designs are removed, with a 5.35dB peak gain and an omnidirectional radiation pattern, and suited for UWB.