Wireless Applications Research Articles

Alternating phase focusing beam dynamics for drift tube linacs

In contrast to conventional E-mode resonance accelerators, H-mode DTLs provide for compact linac sections and have been established as highly efficient resonators during the last decades. Thus, H-mode structures are widely applied for heavy-ion acceleration with medium beam energies because of their outstanding capability to provide high acceleration gradients with relatively low energy consumption. To build upon those advantages, an alternating phase focusing beam dynamics layout has been applied to provide for a resonance accelerator design without internal lenses, which allows for eased commissioning, routine operation, maintenance, and potential future upgrades. The features of such a channel are going to be demonstrated on the example of two interdigital H-mode cavities, separated by an external quadrupole triplet. This setup provides for heavy ion (mass-to-charge ratio A/z≤6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$A/z\\le 6$\\end{document}) acceleration from 300 keV/u to 1400 keV/u and is used as an injector part of the superconducting continuous wave accelerator HELIAC. Hence, this promising approach generally enables effective and compact routine operation for various applications, such as super heavy ion research, material science, and radio biological applications such as heavy-ion tumor therapy.

Dual-Band Millimeter-Wave MIMO Antennas For 5G Wireless Implementation

For 5G wireless applications, this exploration proposes a dual-band 28/38 GHz 4-component MIMO array depending on duplex-mode planar monopole antennas. Four planar monopole antennas are part of the layout framework, situated at the districts of a Rogers RO4003 substrate measuring 20 by 20 mm2 and with a dielectric constant of 3.55. The form of the suggested placoid monopole antenna is crescent-shaped. We created a notch at the bottom and inscribed two rectangular holes on each side to get the required behaviour and execution. For enhancement of isolation, we also employed a limited ground plane. Antenna elements can achieve significant isolation (> − 23 dB) using spatial and scattering behaviour approaches. A illustration of the four-element MIMO array is created, manufactured, and measured to multifariousness the outline idea. The investigational outcomes demonstrate that the suggested antenna has strong isolation and high efficiency while covering the 27.25–29 GHz and 34.5–41 GHz bands. Additionally, studies are done on the channel capacity, realized gain, and radiation pattern. The obtained findings suggest that, for millimeter-wave 5G MIMO implementation, the proposed MIMO antenna might be an excellent application-oriented design.

A micro size terahertz wheel shaped antenna with non-defected ground structure

A micro dimension antenna with wheel-geometrical wide-band terahertz (THz) is suggested in this research. In the circular shaped patch, concentric circle shaped slots are incorporated to form a wheel shaped patch antenna. The suggested model is designed on a polymide substrate with dielectric constant of 4.3 and thickness of 20 µm. The suggested prototype antenna is very much compact in size of 210×160 µm2 . The designed antenna achieves a wideband operation from 8.692 THz to 9.772 THz. This prototype antenna’s maximum realized gain is 10.2 dBi at 9.0 THz. This high gain is important for wide range of wireless applications. The radiation pattern, radiation efficiency, reflection coefficient, surface current distribution and voltage standing wave ratio are examined through the simulation results. In future video rate imaging system, super fast close-range in-door wireless communication, biomedical picturing, homeland defence equipments, security scanning, explosive detection, and characterisation of materials in the THz level will be benefited from the suggested THz antenna.

For wireless LAN application, microstrip patch antenna design in S-band

This article presents a 3.5 GHz rectangular microstrip patch antenna (RMPA) designed, studied, and analyzed for wireless LAN applications. Using Fr-4 as substrate material, whose dielectric permittivity is 4.3, patch thickness is 1.65 mm, and loss tangent is 0.025. A feeding line with an impedance of 50 Ω is utilized to supply the antenna with power. Computer simulation technology (CST) software has been used to design the antenna and origin pro software has been used to display the resulting figures from the simulation. The antenna simulation showed that the return loss is -56.82 dB; the directivity gain is 6.02 dBi, the bandwidth is 0.148 GHz, and the voltage standing wave ratio (VSWR) is 1.0028. The paper aims to increase the return loss, develop a standard VSWR, increase the directivity gain of the antenna, and improve the antenna bandwidth. The results of the proposed antenna were much better than previously published papers, which were suitable for wireless applications. This proposed antenna can be used for future wireless LAN applications.

Mutual coupling reduction between antennas array for 5G mobile applications

This paper introduces the design of a multiple-input-multiple-output (MIMO) antenna optimized for low-profile applications supporting sub-6 GHz fifth-generation (5G) wireless applications. We have started the design from a single antenna with a square patch shape, each antenna array is composed from 4-element radiators fed by using power dividers and quarter microstrip lines. Mounted on a single Rogers RT5880 substrate, the MIMO antenna functions at 3.5 GHz. In order to miniature and to decrease the mutual coupling between the both antennas array we have optimised a magnetic wall based on periodic structures permitting to decrease the mutual coupling between the both antenna array. The unit element from the wall was optimised, studied and validated in order to absorb the surface current and to enhance the isolation between the different radiating elements. The dimensions of the proposed MIMO antenna are 154×220×0.578 mm³. The MIMO antenna final circuit achieves a peak gain of 9 dBi and an isolation around -30 dB. The introduction of the magnetic wall permits to enhance the isolation between the antenna array from -20 dB to -30 dB at 3.5 GHz band. This advancement contributes to the overall performance improvement of the MIMO antenna system.

Dynamic switching from coherent perfect absorption to parametric amplification in a nonlinear spoof plasmonic waveguide

Coherent perfect absorption (CPA) and amplification of electromagnetic waves are converse phenomena, where incoming radiations are coherently dissipated or amplified by structured incidences. Realizing such two phenomena simultaneously in a single device may benefit various applications such as biological sensing, photo detection, radar stealth, solar-thermal energy sharing, and wireless communications. However, previous experimental realizations of CPA and amplification generally require precise controls to the loss and gain of a system, making dynamic switching between the absorption and amplification states a challenge. To this end, we propose a nonlinear approach to realize CPA and parametric amplification (PA) simultaneously at the same frequency and demonstrate experimentally dynamic switch from the CPA to PA states in a judiciously designed nonlinear spoof plasmonic waveguide. The measured output signal gain can be continuously tuned from −33 dB to 22 dB in a propagation length of 9.2 wavelengths. Compared to the traditional linear CPA, our approach relaxes the stringent requirements on device dimensions and material losses, opening a new route to actively modulate the electromagnetic waves with giant amplification-to-absorption contrast in a compact platform. The proposed nonlinear plasmonic platform has potential applications in on-chip systems and wireless communications.

Design of Wideband Energy Capturing Adapter Based on 3-D Meta-Structure for Wireless Power Transmission Application

Design of Wideband Energy Capturing Adapter Based on 3-D Meta-Structure for Wireless Power Transmission Application

4×4 UWB Phased Array Antenna With >51° Far-Field Scanning Range for Wireless Power Transfer Application

4×4 UWB Phased Array Antenna With >51° Far-Field Scanning Range for Wireless Power Transfer Application

Improved design and performance of the global rectenna system for wireless power transmission applications around 2.45 GHz

This work proposes a new conception of the global microstrip rectenna system operating around 2.45 GHz. This improved rectenna system associates a receiving antenna with a rectifier circuit. This rectenna is printed on an FR4 substrate. The proposed antenna is a 1×4 microstrip antenna patch array with pentagonal patches using the defective ground structure method and operates with circular polarization. To show the effectiveness of this array, the results obtained by the computer simulation technology microwave studio (CST MWS) software prove that this array is good in terms of high gain, high directivity, high efficiency, wideband, small volume, and well-adaptation, and all these results are confirmed by another solver high-frequency structure simulator (HFSS). The improved rectifier is a microstrip rectifier that uses an HSMS2852 Schottky diode by using a series topology. The effectiveness of this rectifier is proved by the simulation results using advanced design system (ADS) software in terms of well-matching input impedance, high efficiency, and important output direct current (DC) voltage value. The proposed rectenna system is more efficient compared with the existing works and is very appropriate for several applications of wireless power transmission to power supply electronic instruments in various fields cleanly on our planet.

Single/bidirectional pattern and beamwidth reconfigurable array antenna using reconfigurable reflecting surface

AbstractThis study describes an array antenna that allows for reconfiguration of the three significant antenna properties, that is, radiation pattern, half‐power beamwidth (HPBW), and single and bi‐directional beam. A reconfigurable reflecting surface (RRS) has been designed and incorporated with the array antenna on the top and bottom. The RRS works to reflect or pass the incident electromagnetic wave. It enables us to reconfigure from single to multibeam radiation in the ±z direction. It also provides two levels of HPBW, that is, 49.6° and 95°. Eventually, the same three sets of antennae have been stacked and rotated with a 60° angle to achieve the radiation pattern reconfiguration in the entire azimuth plane. It conforms to reconfigure all three antenna properties in six directions at an equal interval of 60° angle. The achieved maximum gain in a narrow beam is 9.56 dBi. The proposed reconfigurable antenna array can be used in modern wireless communication applications.

Empirical Models of foF2 and hmF2 Reconstituted by Global Ionosonde and Reanalysis Data and COSMIC Observations

AbstractThe F2‐peak plasma frequency (foF2) and the height of the F2 peak (hmF2) are two of the most important parameters for any ionospheric model, as well as radio propagation studies and applications. In this study, we have developed empirical models to capture the most significant variations of foF2 and hmF2. The derived empirical models (referred to as the USTC models within this study) are specified through global ionosonde and reanalysis data based on the International Reference Ionosphere (IRI) Consultative Committee on International Radio (CCIR) method and Constellation Observindg System for Meteorology, Ionosphere, and Climate (COSMIC) observations based on the empirical orthogonal function analysis, respectively. The USTC models are validated against the IRI CCIR model prediction. The comparison results revealed that the empirical foF2 model performs better in capturing the foF2 variations than the IRI CCIR model, which can overcome the underestimation of the IRI CCIR model at low latitudes. Although the IRI CCIR model overestimation at middle latitudes is addressed by the empirical hmF2 model, the visible differences between the model predictions and ionosonde observations still exist at low latitudes, which could be attributed to the significant difference between COSMIC and ionosonde hmF2 measures.

A Compact Self Isolated UWB-MIMO Antenna with WiMAX and WLAN Band Notched Characteristics for Portable Wireless Applications

A Compact Self Isolated UWB-MIMO Antenna with WiMAX and WLAN Band Notched Characteristics for Portable Wireless Applications

At 28 GHz microstrip patch antenna for wireless applications: a review

At 28 GHz microstrip patch antenna for wireless applications: a review

Miniaturization of antenna using metamaterial loaded with CSRR for wireless applications

This paper proposes a compact decagon antenna for wireless applications based on inspired metamaterial (MTM) loaded with a modified complementary split ring resonator (CSRR). A MTM loaded with CSRR is used to achieve a size reduction of 50% when compared to a traditional antenna. The suggested decagon antenna's ground plane has been loaded with CSRR. The antenna was made on an FR4 substrate with a thickness of 1.6 mm and εr=4.4 and has a very small dimension of 0.288 λ_0x0.272 λ_0x0.013 λ_0 (where λ_0 represent center frequency at 2.4 GHz). The given antenna has a 90 MHz bandwidth (2.40-2.50 GHz) with a peak gain of 2.36 dB. The presented design is validated by showing simulated results of the S parameter, VSWR, gain, surface current, and radiation pattern. The proposed antenna is well suited for wireless applications.

Design of a Circularly Polarized Planar Monopole Antenna with a Simplified Radiator Structure for UWB Applications

The demand for wideband circularly polarized (CP) antennas in wireless communication applications has been increasing, given that it offers reliable signals with reduced interference. In particular, planar monopole antennas are a popular choice for use in CP applications due to their compact size and ease of integration. However, achieving CP characteristics often requires complex modifications, an increased antenna size, and design complexity. To address these challenges, this study proposes a simplified radiator structure modification for CP planar monopole antennas and validates the performance of the proposed antenna for ultra-wideband (UWB) applications by conducting both frequency-domain and time-domain analyses. The size of the proposed antenna is 34 mm × 41 mm × 1.6 mm, with FR-4 as the substrate. Both the -10 dB <i>S</i><sub>11</sub> bandwidth and 6 dB axial ratio axial ratio is 3.46–5.5 GHz, with the radiation patterns in the frequency range of interest being omni-directional. The proposed UWB CP antenna also yields decent antenna performance in time-domain analyses, such as the antenna fidelity factor and the system fidelity factor.

Design and Development of Conformal Body Centric Antenna for WBAN Application

In this paper, a conformal body centric antenna for wireless body area network (WBAN) applications is discussed. These designs are low-cost, low-profile circular and ring-shaped monopole antennas. Operational frequency of antenna is range from 2.5–10.6 GHz to meet the requirements of WBAN systems. The antenna is intended to be body- centric and conformal, which means for best performance, it is placed close to the body and conforms tothe shape of the human body. The radiation patterns are measured at 2.5 Ghz frequency. The substrate used for design is FR-4. The simulation results show that the proposed antenna has good impedance matching, a broad bandwidth of 122 MHz, and a gain of 4.8 db. The radiation pattern of the antenna is omnidirectional, which is desirable for wireless communication applications. Monopole antenna is designed and simulated using the Ansys EDT (HFSS) software. The monopole antennas are also fabricated in real time with proposed specifications. The proposed antenna can be used in various wireless communication systems such as WLAN, RFID, and Bluetooth, where low cost, compact size and critical design are considered.

Fractal Metasurfaces and Antennas: An Overview for Advanced Applications in Wireless Communications

This paper provides an overview of fractal antennas and metasurfaces, exploring their design principles, performance, and applications. Fractal antennas, incorporating self-similar geometric shapes, offer several advantages, such as their multiband operation, compact size, and improved performance. Metasurfaces, on the other hand, are two-dimensional structures composed of subwavelength unit cells and are designed to achieve advantageous and unusual electromagnetic properties by enabling precise control over electromagnetic waves. This paper discusses the fundamental concepts of fractal antennas and metasurfaces, compares their characteristics, and presents the latest advances in research. Additionally, it highlights applications in wireless communications, energy harvesting, sensing, and beyond.

Nonlinear Capacitance Compensation Method for Integrating a Metal–Semiconductor–Metal Varactor with a Gallium Nitride High Electron Mobility Transistor Power Amplifier

A nonlinear capacitance compensation technique is presented in this paper to enhance the linearity of a power amplifier (PA) in the GaN process. The method involves placing an MSM varactor device alongside the GaN HEMT device, which works as the amplifying unit such that the overall capacitance observed at the amplifier input is constant, thus improving linearity. This approach is a reliable and straightforward way to improve PA linearity in the GaN process. The proof-of-concept prototype in this study involves the fabrication of a PA device using a standard GaN HEMT process, which successfully integrates the proposed compensation technique and demonstrates excellent compatibility with existing processes. The prototype has a saturation output power of 18 dBm, a peak power-added efficiency of 51.8%, and a small signal gain of 15.5 dB at 1 GHz. The measured AM–PM distortion at the 5 dB compression point is reduced by more than 50% compared to that of an uncompensated device. Furthermore, the results of third-order intermodulation distortion demonstrate the effectiveness of the linearity enhancement concept, with values improved by more than 5 dB in the linear region compared to those of the uncompensated device. All of the results demonstrate the potential utility of this design approach for wireless communication applications.

Weighted Visibility Graph Based WiFi Indoor Positioning Method Using Heuristic Optimization

With the widespread use of wireless communication technologies and IoT applications, researchers are developing approaches that utilize WiFi signals for indoor location determination. In this study, indoor positioning process based on heuristic optimization-based methods was performed by creating weighted visibility matrices of access points based on WiFi signal strength (RSSI) values. In the proposed method, the PSO and GA approaches determine the position of the mobile user using a common fitness function based on the visibility weight matrices. The proposed method has been tested on a virtual scenario where position ranges based on RSSI ranges are determined. Both heuristic optimization methods are compared according to different criteria and the positioning process is performed with a maximum error of 3m for the GA based method and a maximum of 1.5m for the PSO based method.

Synergistic terahertz shielding effects of electrically conductive MXene and shape-controlled magnetic nickel in polyvinylidene fluoride (PVDF) composites

Terahertz (THz) shielding materials have garnered significant attention due to various potential applications in wireless communication, sensing, and defense. In this study, we present efficient THz shielding performance of polyvinylidene fluoride (PVDF) polymer composites incorporated with a mixture of MXene and shape-controlled nickel (Ni) nanoparticles. The PVDF/MXene/Ni composites demonstrated exceptional absorption coefficient and shielding effectiveness against unwanted THz electromagnetic waves, owing to the remarkable synergistic effect between electrically conductive Ti3C2Tx MXene and magnetic nickel nanoparticles. Notably, magnetic properties of Ni nanoparticles were controlled by external magnetic field applied during the synthesis process. Flower-like Ni nanoparticles synthesized under an external magnetic field exhibited enhanced magnetic properties compared to spherical Ni nanoparticles synthesized without an external field. As a result, a 20-µm thick PVDF/MXene/Ni composite film, with a 10 wt.% loading of flower-like Ni nanoparticles, demonstrated the THz shielding effectiveness of 34 dB at 1 THz. This shielding performance surpasses those of composite containing spherical Ni nanoparticles (26.7 dB) as well as previously reported shielding materials. These findings highlight an effective approach to tailor the THz shielding properties of polymer composites by modifying the composition and morphology of conductive and magnetic fillers.