Antennas - Science topic

The article shows that the Archimedean spiral, usually described as a smooth spiral, can be transformed in many different shapes. The main part of the article concentrates on the curvature of the transformed spirals. It will also be shown that the shape some of them is an approximation of spiral antennas.

A balise is an electronic beacon or transponder placed between the rails of a railway as part of an automatic train protection system. The French word balise is used to distinguish these beacons from other kinds of beacons. A Eurobalise is a specific type of a balise installed between the rails of a railway. Eurobalises are part of the European tra...

As large-scale low Earth orbit (LEO) constellations continue to expand, the potential of their signal strength for positioning applications should be fully leveraged. For high-precision angle of arrival (AOA) estimation, current spectrum search algorithms are computationally expensive. To address this, we propose a method that downscales the 2D joi...

Light controlled phased array has the advantages of fast response speed, compact system, diverse functions, and flexible control, and has been widely applied in many scientific and technological fields. Optical true delay technology (OTTD) is the most direct technical means to achieve phase delay of optical carrier signals, and it is also the most...

Trabajo Fin de máster sobre: Las torres de telecomunicaciones como soporte para las infraestructuras de telefonía, radiodifusión o enlaces de microondas entre otros, son una pieza clave para la actual sociedad de la información. Garantizar su correcto funcionamiento de manera ininterrumpida, su adaptación a las nuevas tecnologías inalámbricas y la...

This paper presents a novel Ku-band parasitic patch antenna based on MEMS technology. The antenna consists of two substrates that are bonded together. The lower substrate houses the main patch and the ground layer, while the upper substrate supports the parasitic patch. To minimize the dielectric loss, the parasitic patch is fabricated using a doub...

The measurement and analysis of the interaction between Bessel vortex electromagnetic (EM) and several standard targets are presented in this paper. With the aid of the angular spectrum expansion (ASE) method and physics optics (PO) theorem, scattering results on the plates (metal and dielectric) and a sphere could be derived. Furthermore, plane ne...

We have successfully demonstrated three 4 × 2 hot electron bolometer (HEB) mixer arrays, designed to operate between 4.2 and 5.5 K, with local oscillator (LO) frequencies of 1.4, 1.9, and 4.7 THz, respectively. These arrays consist of spiral antenna coupled NbN HEB mixers combined with elliptical lenses. These are to date the highest pixel count ar...

configuration of field distribution for a diversity frequency is represented for exploring. Ones, influenced surrounding field by rays' interference of the propagated waves. Secondly, regularity of field pattern when these signal rays are received as foot print. Introduction: Sustainable development programs can rely on communication systems. Frequ...

In recent research study, non-orthogonal multiple access (NOMA) has been shown to be one of the radio access technologies that is 5G compatible in the sense that it practically increases the spectral efficiency of system latency reduction. This work presents performance evaluation of multiple antenna non-orthogonal multiple access (NOMA) system in...

with the advancement in microelectronic technology,there is a growing tendency in the hardware of the wirelesscommunication systems to be smaller in size with much morefunctionalities. Along with this miniaturized RF systems andcomponents, the size of the antenna becomes one of the largestand cumbersome system components. As a result, small size, l...

An ear-bar true wireless stereo (TWS) earphone antenna is designed and analysed to enhance the radiation efficiency, path gain with reduced specific absorption rate (SAR). The proposed design consists of a meander line structure printed on a flexible substrate of polyimide material. The antenna works for ISM band applications covering the frequency...

Flexible electromagnetic metamaterials are a potential candidate for the ideal material for electromagnetic control due to their unique physical properties and structure. Flexible electromagnetic metamaterials can be designed to exhibit specific responses to electromagnetic waves within a particular frequency range. Research shows that flexible ele...

To improve the received signal strength beams are formed by multi-element arrays. These beams are focused on the direction of arriving signals, with an intention of maximizing the received signal power. The signals with noise and interference arrived from a distinct direction will be estimated by Uniform Linear Array (ULA) with 10 antenna elements....

In this article, a novel method of achieving a single-layer, dual-band, dual-circularly polarized (CP) shared-aperture phased array antenna with wide beam scanning coverage is presented. The space antenna was designed to provide direct-to-cellular communications services at S-/C-bands with a frequency ratio of 1:1.8. Using novel ceramic substrates...

Sistem pemantauan Komatsu Machine Tracking System atau Komtrax, menggunakan teknologi komunikasi seluler dan berbasis internet yang canggih. Komtrax sebagai sistem pemantau pada unit alat berat Komatsu seperti HD 785-7 dinilai penting sebab kendala-kendala yang muncul pada sistem ini, seperti hilangnya transmisi sinyal akan berdampak negatif pada k...

The results of experimental studies of a 60 GHz lens antenna are presented to improve its characteristics based on the photonic jet effect. It is shown that placing a dielectric cube on the open end of a waveguide according to the "plug-and-play" principle leads to an increase in the antenna gain up to 5 dBi without changing the design of the lens...

This paper proposes a novel joint channel-estimation and source-detection algorithm using successive interference cancellation (SIC)-aided generative score-based diffusion models. Prior work in this area focuses on massive MIMO scenarios, which are typically characterized by full-rank channels, and fail in low-rank channel scenarios. The proposed a...

This paper investigates an innovative movable antenna (MA)-enhanced multiple-input multiple-output (MIMO) system designed to enhance communication performance. We aim to maximize the energy efficiency (EE) under statistical channel state information (S-CSI) through a joint optimization of the transmit covariance matrix and the antenna position vect...

Coupled‐cavity mini‐array vertical‐cavity surface‐emitting lasers (VCSELs) are promising laser sources for high‐speed data transmission due to their extended intensity modulation frequencies. Here, it is demonstrated for the first time how to use such a 2 × 1 mini‐array VCSEL for the photonic generation of CW THz radiation. The emission frequencies...

Active optical antennas, a novel Schottky photodiode design, have drawn significant attention due to their advantages of near‐field enhancement and hot‐electrons generation for sub‐bandgap photodetection. However, the reported active antenna‐based Si Schottky photodetectors have shown low photoresponse in a limited wavelength range below 1650 nm. T...

Fluorescent antennas (FAs) exhibit considerable promise in optical wireless communication (OWC), primarily due to their advantages over conventional optical systems in terms of optical gain and field of view (FoV). This paper presents a COMSOL-based model designed to optimize external light-concentrating structures for FAs, with its accuracy valida...

This paper presents the outcomes of a feasibility study on the manufacturing of D-band horn antennas through the Low Power Bed Fusion process. Different prototypes have been realized and tested, showing nice results in terms of the co-polarization component. On the other hand, a spurious cross-polarization component is present in the radiation patt...

For the application scenario of multi-user, high-bandwidth laser communication in satellite internet, this paper proposes a spatiotemporal vector optimization algorithm to achieve high energy utilization in arbitrary multi-beam generation using a liquid crystal optical phased array antenna. The core components of this method involve optimizing phas...

This letter presents a 256‐element ultra‐wideband active phased array tile spanning 3–15 GHz. The array employs Vivaldi antennas arranged in a triangular lattice, optimizing the T/R module count. The ultra‐wideband T/R module, based on system‐in‐package (SiP) technology, integrates power amplifiers, low‐noise amplifiers, and multifunctional chips....

This paper proposes a dual-band co-aperture antenna, which covers 2.09–11.61 GHz (9.52 GHz, 138.9%) and 21.6–29.6 GHz (8 GHz, 31%). The overall size of the proposed antenna is 0.76 × 0.76 × 0.37 λ03, where λ0 is the free space wavelength of the lowest operating frequency of 2.09 GHz. By removing the internal metal of the monopole antenna and adding...

This article presents a study on the influence of antenna parameters in medical microwave radiometers on brightness temperature. A series of computational experiments was conducted to analyse the dependence of brightness temperature on antenna characteristics. Various antenna parameters and their effect on the distribution of electromagnetic fields...

Nonlinear resonances of plasma waves in field-effect transitors enable a well-known photodetection mechanism, first introduced by Dyakonov and Shur in the Nineties, especially suited to the Terahertz (THz) frequency range. Theoretical analyses of the mechanism always assume that the gate of the transistor, which is coupled to the antenna receiving...

An eight-element MIMO antenna with a neutralization line was utilized for future 5G mm-wave applications. The MIMO configuration was designed for two ports, four ports and eight ports to validate the desired impedance and radiation characteristics. The measured results in terms of MIMO and scattering parameters correlate well with the simulated one...

This study introduces the development of a flexible and compact radiator using a jeans material as a substrate for wireless body area network (WBAN) applications. A fabric made of jeans with a thickness of 0.6 mm, a tangent loss (tan δ) of 0.02, and a dielectric constant (εr) of 1.6 is used for designing an element with dimensions of 18.5 × 27 × 0....

The paper presents a description of a new species of the genus Cephalotoma Lesne, caught in northern Thailand. The new species, C. patcharinae Borowski n. sp., is the first species in the Oriental region with a two-segmented club of antennae. The effect of the discussion presented in the paper is synonymising the tribe Cephalotomini Liu and Schönit...

PROBLEM STATEMENT: The performance and size constraints of the current railway mobile communication systems force the development of more effective communication methods. OBJECTIVES: This study aims to build a quasi-microstrip Yagi antenna with a 900MHz centre frequency that minimizes the antenna's physical dimensions and improves communication cap...

With video streaming now accounting for the majority of internet traffic, wireless networks face increasing demands, especially in densely populated areas where limited spectral resources are shared among many devices. While multi-user (MU)-MIMO technology aims to improve spectral efficiency by enabling concurrent transmissions over the same freque...

The swift advancement of contemporary communication technology, along with the development of radar systems, has raised the requirements for antenna systems. In this work, an integrated array antenna operating in the 24 GHz and 77 GHz frequency bands is proposed. The microstrip antenna array element uses a width reduction approach to reduce its vol...

Tree roots can support and transmit nutrients for trees healthy growth aboveground, which greatly improve trees productivity and have significant effect on maintaining the normal operation of ecosystem. In order to map the tree roots more efficiently and effectively, the nondestructive ground penetrating radar is introduced into this area. The cons...

This study investigates a high-gain, miniaturized antenna array featuring semicircular Defected Ground Structures (DGSs) based metamaterial designed for wideband smartphone applications. The antenna array, measuring 49 × 25 mm 2 , is constructed on an FR4 substrate with a dielectric constant of 4.3 and a thickness of 1.6 mm. The design incorporates...

Este trabajo analiza el uso de WhatsApp como canal de difusión de noticias por parte de Antena 3 Noticias e Informativos Telecinco. Los objetivos incluyen examinar los criterios de uso de los canales de difusión en WhatsApp y explorar las características de las noticias publicadas y las reacciones de los usuarios. Se sigue una metodología basada en...

A planar wideband quasi-Yagi antenna for vehicular application is proposed in this paper. The presented antenna composed of microstrip to slot line transition (MST), coplanar striplines, a driver diamond dipole, and seven parasitic elements. The diamond dipole is linked to the ground plane through coplanar strip lines. The bandwidth of the designed...

In this paper, a multilayer monopulse antenna at Ku-Band with high efficiency, high power handling capability, high gain, 45° linear polarization and low sidelobe is presented. A new slot antenna is proposed as a radiating element based on a cavity-backed slot-coupled patch antenna. Using an enclosed cavity structure reduces coupling between antenn...

This article introduces a compact (32 × 64 × 0.8 mm³) four port MIMO antenna for K-band for satellite and for band 5G NR- n257, n258 & n261 for mmWave applications. The proposed antenna is designed at 24 GHz and selected an optimal design (Stage 3) after successive analysis of different stages (Stage 1, Stage 2 & Stage 3) performance. The radiating...

Terahertz (THz) generation via photomixing on photoconductive antenna using twin delayed chirped pulses provides a long THz pulse with a narrow bandwidth. To generate a long pulse with a broad bandwidth, we propose a new, to the best of our knowledge, method that combines two long optical pulses with opposite chirps. The pulses exhibit temporal dis...

In this paper a 5G compact antenna is investigated at 28 GHz. The structure is based on Quasi-Yagi antenna comprising a director, driver, and reflector. The SIW technology is utilized to feed the antenna because of its numerous benefits. The antenna array is designed and simulated and the S11, E pattern, and H pattern are analyzed for both single-e...

Lower hybrid wave (LHW) current drive plays a crucial role in sustaining steady-state (SS) discharges on the Experimental Advanced Superconducting Tokamak (EAST). Hotspots frequently form on the wave antenna and guard limiters during SS operations. Although both experimental and theoretical studies suggest that fast electrons could be responsible f...

This research paper proposes three joint transmit and receive (TX/RX) beamforming schemes for minimizing the bit error rates of next-generation wireless sensor networks. Based on minimizing the optimization problem of the total mean squared error between the transmitted and received data symbols, the first beamforming scheme is proposed. The second...

We present a study of the transverse size of parton showers and their diminishing interaction with the medium in the high virtuality stage of jet evolution. We consider the process of a hard quark produced in deep inelastic scattering off a large nucleus. Single gluon radiation from this quark, in the absence of scattering, is re-derived using wave...

This study investigates the conditions under which gravitational waves (GWs) are emitted during the merger of hot white dwarfs (WDs) in a binary system. Traditionally, these systems consist of two low-mass stars or a more massive WD paired with a less massive companion. In addition, recent work has investigated the possibility that double white dwa...

This paper presents the design and fabrication of a 4×4 array antenna based on multi‐mode horn elements and sequential feeding network. The multi‐mode horn antenna is a structure that can suppress grating lobes and side lobe levels by excitation and combining different modes of electromagnetic wave radiation. The sequential feeding network is a tec...

The permittivity of absolute vacuum is equal to zero. The interior of a proton contains a lattice with a small positive permittivity. By adjusting the size of the atomic nucleus slab, the antenna (proton) can achieve high gain due to transmission resonance, and the cosmic background radiation is amplified into matter.

The proposed article offered a closely packed circularly polarized MIMO antenna system for a 5G NR n48/n78 communication system. The design consists of an E‐shaped antenna with modified arms along with shorting pins, and the edge‐to‐edge distance between the radiator is 0.2 mm. The proposed design offers isolation from 15 dB(minimum) to 47.35 dB(ma...

This paper investigates methods to enhance antenna's channel information extraction capabilities in wireless communications, particularly in challenging multi‐path environments. Focusing on the issues of channel information loss due to multi‐path superposition at the receiver and multi‐path fading during wireless channel propagation, this paper uti...

This paper introduces a novel dual-band Multiple-Input Multiple-Output (MIMO) antenna specifically crafted for 5G millimeter-wave communication systems. The antenna is designed to operate within the frequency spectrum of 26 to 31 GHz and 34.5 to 40 GHz. Notably, at 28 GHz, the antenna attains an impressive gain of 10.6 dBi, coupled with an efficien...

Single-snapshot signal processing in sparse linear arrays has become increasingly vital, particularly in dynamic environments like automotive radar systems, where only limited snapshots are available. These arrays are often utilized either to cut manufacturing costs or result from unintended antenna failures, leading to challenges such as high side...

This work focuses on analyzing the outage probability (OP) in a downlink multi‐user multiple‐input multiple‐output non‐orthogonal multiple access (MIMO‐NOMA) system, specifically employing the maximum‐ratio transmission/receive antenna selection structure. In the investigated system, the user close to the base station (BS) acts as a full‐duplex (FD...

In this article, we propose a new hypothetical differential model with many free parameters, which makes it attractive to users. The motivation is as follows: an extended model is proposed that allows us to investigate classical and newer models appearing in the literature at a "higher energy level", as well as the generation of high-order Melnikov...

(Eu3+4[PTC]4-3)0.78(Eu3+[TREN-1,2-HOPO]3-)0.22 inorganic-organic hybrid nanoparticles (IOH-NPs) contain Eu3+, tris[(1-hydroxy-2-oxo-1,2-dihydropyridine-6-carboxamido)ethyl]amine (TREN-1,2-HOPO) and perylene-3,4,9,10-tetracarboxylate (PTC). The IOH-NPs are prepared in water and exhibit a rod-type shape, with a length of 60 nm and a diameter of 5 nm....

The domain decomposition method (DDM) enables efficient simulation of electromagnetic problems in large-scale array antennas using full-wave methods on moderate hardware. This paper introduces and compares two nonoverlapping DDMs serving as preconditioners with outstanding simulation efficiency. The first method targets finite periodic array antenn...

This paper presents a microstrip patch antenna array integrated with metamaterial (MTM) to improve performance at the 2.4 GHz frequency band. The antenna array consists of two patch elements placed side by side on an FR4 epoxy substrate with coaxial feeding. To address mutual coupling, a metamaterial structure based on concentric split rings is int...

A broadband ±45° dual-polarized base-station antenna based on crossed-dipoles with parasitic elements has been presented in this study. This antenna consists of printed dipoles fed by integrated baluns, parasitic elements, and a ground plane below them. As a result of using parasitic elements on the dipoles and creating a suitable coupling between...

The production of consumer electronics using electrically conductive materials is a dynamically developing sector of the economy. E-textiles (electronic textiles) are also used in radio frequency identification technology, mainly in the production of tag antennas. For economic reasons, it is important that the finished product is universal, althoug...

Com a pressão constante para produzir conteúdos em tempo real, as fast-news tornaram-se um elemento central na cobertura jornalística, contribuindo para a superficialidade informativa e influenciando a perceção pública. No caso da política, o partido Chega e a sua imagem nas eleições legislativas de 2024 são um claro exemplo desta realidade. Desde...

Herein, the first English article demonstrating the Yagi-Uda antenna is introduced. The article was originally published in the Proceedings of the Imperial Academy of Japan in 1926.

This letter demonstrates for the first time how laser induced deep etching (LIDE) technology is used to manufacture highly precise glass dielectric resonator antenna (DRA) for sub‐THz applications. The glass resonator antennas shown in this letter operate in the 110–170 GHz (D‐band) frequency range, which is highest frequency at which glass dielect...

We improve upon previous low-cost radio scintillation monitor designs by implementing onboard processing and display capabilities to produce a more comprehensive device. The proposed design uses a U-blox EVK-6T’s GPS receiver, providing data updates at a rate of 1Hz, and a Raspberry Pi 4. The RPi calculates the S4c index with both a three-minute an...