Traditional Antenna Research Articles

Miniaturized Arrow-Shaped Flexible Filter-Embedded Antenna for Industrial and Medical Applications

This paper presents the design and characterization of a coplanar waveguide (CPW) fed, low-profile, and flexible arrow-shaped filtenna for ISM band applications at 2.45 GHz. The antenna design involves an innovative approach incorporating etching slots to achieve miniaturization by 34%, contrasting with a traditional quadrilateral-shaped antenna. After the attainment of desired miniaturization, the unwanted harmonics are also mitigated by deploying simple filtering methodology. A perpendicular rectangular stub is strategically introduced to the feedline, effectively minimizing harmonics across a broad frequency range of 3.3–11.0 GHz. Through simulations and measurements, the results indicate that the antenna’s operational band spans from 2.276 to 2.75 GHz, encompassing the entire ISM band (2.4–2.5 GHz). Notably, the antenna demonstrates promising radiation characteristics, including omnidirectional gain of approximately 2.2 dBi and a radiation efficiency exceeding 95%. With a compact overall size of 0.24λ × 0.20λ × 0.0005λ (where λ is the free-space wavelength at 2.45 GHz), coupled with wide harmonic rejection property, the proposed arrow-shaped flitenna emerges as a compelling candidate for ISM band applications.

A dual-port MIMO antenna system for 5G and Wi-Fi 6E communications using a parasitic element

The increasing demand for high-speed, reliable wireless communication necessitates innovative antenna designs that can efficiently support emerging technologies such as 5G and Wi-Fi 6E. Traditional antenna solutions often struggle to meet the compactness, isolation, and efficiency requirements posed by these advanced systems. This research addresses these challenges by introducing a compact dual-hook multiple input multiple output (MIMO) antenna specifically tailored for 5G and Wi-Fi 6E applications. The proposed antenna offers dual-band operation in a small size with high isolation at both resonance frequencies (3.6 GHz and 7.1 GHz). The novel design has a simple and low-profile structure and can be easily integrated into practical applications. It reduces the cost and complexity of the system. The MIMO technology has a good reflection coefficient, a good efficiency and a maximum gain of 3.85 dB. To enhance the effeciency of this structure, parasitic element and defective ground structure (DGS) are combined. The twin-hook radiators are printed symmetrically on the top layer of low-cost FR-4 substrate with a small size of 19 × 36 mm2 (0.23 λ0 × 0.45 λ0, with λ0 is the guided wavelength at the lowest operating frequency). In addition, the DGS is formed by cutting two symmetrical slots into the semi-ground plane to provide better impedance matching at both resonant frequencies. Based on the simulation findings, the -10dB return loss bandwidth of the proposed structure reaches approximately 14,08% and 10,21% for 3.6GHz and 7.1GHz, respectfully. On the other hand, high isolation is obtained, reaching over -21 dB in the low frequency band and -29 dB in the high frequency band. Also, for verification of MIMO system characteristics, diversity gain (DG), envelope correlation coefficient (ECC), total active reflection coefficient (TARC) and channel capacity loss (CCL) are analysed and used to investigate the proposed MIMO antenna diversity performance.

Passive wireless RFID strain sensor for directional-independent structural deformation monitoring

The advancement of Radio-frequency identification (RFID) sensor technology presents a novel approach to monitoring the health of structures. However, the traditional RFID antenna sensor encounters issues with limited sensitivity and strain measurement capabilities in a single direction. In this investigation, we propose, model, analyze, and test an enhanced wireless and passive RFID strain sensor that offers improved sensitivity to strains and quantifiable measurements in orthogonal directions. Theoretical analysis based on multiphysics elastodynamics and electromagnetics illustrating the resonant response and distribution of current field density between two sets of orthogonally installed sensors under applied stress. Our findings reveal that the RFID strain sensor exhibits characteristics to electromagnetically induced transparency like (EIT-like) effect, enabling independent and intensified measurement of strains both horizontally and vertically. Experimental data demonstrates a linear correlation between the shift in resonant frequency of the sensor antenna and transverse strains as well as longitudinal strains, with sensitivity coefficients measuring −1.76 kHz με−1 for transverse strain and 2.17 kHz με−1 for longitudinal strain respectively. Consequently, by accurately analyzing variations in resonant frequency it becomes possible to deduce both magnitude and direction of strains on the antenna effectively laying groundwork for future engineering applications.

High-Efficiency Microwave Wireless Power Transmission via Reflective Phase Gradient Metasurfaces and Surface Wave Aggregation.

Microwave Wireless Power Transfer (MWPT) technology is crucial for emergency power supply during natural disasters and powering off-grid equipment. Traditional antenna arrays, however, suffer from low energy capture efficiency, difficult impedance matching, complex synthetic networks, and intricate manufacturing processes. This paper introduces a microwave energy receiver design utilizing Reflective Phase Gradient Metasurfaces (R-PGMs) and surface wave energy convergence technology. The design leverages the effective plane wave-to-surface wave conversion capability of R-PGMs to transform incident microwave energy into a surface wave mode, which is then efficiently harvested using a circular energy convergence array before being output to a coupling port. By optimizing R-PGM parameters, an ideal 60° phase gradient distribution is achieved, facilitating the focus of surface wave energy via dispersion characteristics. These components are integrated into a hybrid antenna array, complemented by a matched energy output port structure. Numerical simulations show that this array can efficiently convert microwave energy from plane waves to surface waves, achieving a conversion efficiency of 85.32% and a collection efficiency of 68.26%. Experimental results corroborate these findings, with peak energy collection efficiency reaching 64.68% at 5.8 GHz and an RF-DC conversion efficiency of 42%, confirming the design's efficacy. Compared to conventional methods, this design simplifies the system by avoiding complex combining networks and significantly enhances the efficiency of microwave MWPT.

Compact Ultra-Wideband MIMO Antenna for 5G Communication Systems

Ultra-wideband (UWB) technology is highly respected in modern communication systems because it can enable high-speed, high-data-rate communication over short distances. It is still difficult to achieve optimal multiple-input multiple-output (MIMO) performance in real-world multipath settings, even with breakthroughs in traditional antenna designs. UWB-MIMO antenna solutions have been created and simulated in order to address this problem and fulfill present demands. Nevertheless, maintaining high antenna efficiency and the requirement for antenna designs tailored to a particular bandwidth are two of the difficulties UWB systems must overcome. Recently, a variety of optimization strategies have been employed to obtain high gain and UWB performance by fine-tuning antenna characteristics. The major obstacles are resolved by the optimization process, including the time and computational resource requirements. The difficulty is further compounded by the intricacy of accurately modifying antenna settings to maximize gain. A multi-objective advancement for the design and improvement of the reduced UWB-MIMO test radio wire for 5G was offered as a solution to these problems. In order to attain the UWB feature, we first aim to use a single elliptical-square form antenna that operates from 3.4 to 70 GHz with isolation larger than 29.54 dB. Furthermore, we optimize the impedance bandwidth by tuning the parameters of the structural dimensions using the improved proportional topology optimization (IPTO) technique. Additionally, we present the orthogonal correction using the binarized convolutional neural network (BCNN).

A Wide-Beam Antenna for Automotive Radar Based on Improved Particle Swarm Algorithm

Article A Wide-Beam Antenna for Automotive Radar Based on Improved Particle Swarm Algorithm Bin Wang 1, Zhenhua Li 1 and Shufei Yin 1,2,* 1 Shanghai Baolong Automotive Corporation, Shanghai 201619, China 2 School of Automotive Engineering, Wuhan University of Technology, Wuhan 430070, China * Correspondence: yinshufei@chinabaolong.net Received: 26 August 2024; Revised: 9 September 2024; Accepted: 11 September 2024; Published: 23 September 2024 Abstract: The traditional automotive corner radar antenna has the problem that the horizontal filled of view (FOV) is not large enough, which affects wide detection area capability and driving safety. In order to solve the problem, this paper proposes a wide-beam antenna design method for automotive corner radar based on improved particle swarm optimization (IPSO) algorithm. The mathematical model of comb-line antenna for 77 GHz corner radar is established and combined with the IPSO algorithm to achieve wide beam. The algorithm avoids the search process falling into local optimum by introducing an adaptive shrinkage factor and chaotic disturbance when the non-superior particle position is updated. The computational results show that the convergence of the IPSO algorithm is significantly better than standard particle swarm optimization (SPSO) in wide beam forming under the same number of iterations.

High gain MIMO antenna with multiband characterization for terahertz applications

Recently, the relevance of multiple input multiple output (MIMO) technology has increased due to the growing user base and the surge in demand for high data rates. It provides an essential answer to the pressing requirement for high-capacity communication systems compliant with new standards. In this study, a four-element MIMO antenna with specific properties—a thickness of 0.0224 mm and a relative permittivity of 4.3 —is presented on a polyamide substrate. It is intended to operate in terahertz (THz) applications at 0.395 and 0.629 THz. The configuration of the antenna is based on a traditional fork antenna. At the resonant frequencies, this MIMO antenna can achieve bandwidths of 9.53 GHz and 24.19 GHz, with reflection coefficients of -16.19 dB and -24.27 dB, respectively. Moreover, a gain of 5.17 dB and 3.19 dB are obtained at the second and first resonant frequencies, respectively. In the effort to maintain the operational band and enhance gain, a significant challenge arises from the insufficient isolation between the four antenna elements within the limited space. A Defected Ground Structure (DGS) is constructed and the inter-element distance is carefully investigated in order to effectively address this issue. Mutual coupling effects are effectively reduced with this antenna, and an amazing MIMO diversity response is shown. Additionally, it achieves a mean effective gain of less than -3, envelope correlation coefficients below 0.0125, diversity gain of around 10 dB, and total active reflection coefficients below -4 dB. The suggested design was simulated using the ansys High-Frequency Structure Simulator program. These enhancements show that the recommended MIMO antenna is a suitable choice for terahertz applications like 5 G networks of the future and terahertz imaging systems used in medical settings for tissue imaging and cancer diagnosis.

A Corrugated Edged Tapered Slot Antenna with Low Cross-Polarization and Moderate Gain for Phased Array Systems

ABSTRACT This paper presents a miniaturized Vivaldi antenna with a scan volume of ± 30° designed for the 6–18 GHz tactical operational band, commonly employed in phased array systems and modern surveillance applications. The proposed antenna offers enhanced radiation characteristics, low cross polarization, broad beam width, and moderate gain. The design presented in this paper follows a step-by-step approach to achieve enhanced performance in terms of multi-octave bandwidth and compact size. Initially, a traditional Vivaldi antenna was designed and examined, with a modified feed structure. Subsequently, corrugated edges were inserted into the antenna, increasing its electrical length and resulting in good impedance matching, especially in the 6–10 GHz frequency band. A prototype model is fabricated and tested to validate its performance against the simulation results. The measured results demonstrate that the return loss (S11) remains below −10 dB across the operating frequency range, achieving a 50% bandwidth, with a gain of 3–7 dB, and improved co-cross polarization of −23 dB at 6 GHz and −26 dB at 18 GHz.

A Compact Wearable Textile Antenna for NB-IoT and ISM Band Patient Tracking Applications.

This paper proposes a novel multi-band textile monopole antenna for patient tracking applications. The designed antenna has compact footprints (0.13λ02) and works in the narrow band-internet of things (NB-IoT) 1.8 GHz, radio frequency identification (RFID), and industrial, scientific, and medical (ISM) 2.45 GHz and 5.8 GHz bands. The impedance bandwidths and gain of the antenna at 1.8 GHz, 2.45 GHz, and 5.8 GHz are 310 MHz, 960 MHz, and 1140 MHz; 3.7 dBi, 5.3 dBi, and 9.6 dBi, respectively. Also, the antenna's behavior is checked on different body parts of the human body in various bending scenarios. As per the evaluated link budget, the designed antenna can easily communicate up to 100 m of distance. The specific absorption rate values of the designed antenna are also within acceptable limits as per the (FCC/ICNIRP) standards at the reported frequency bands. Unlike traditional rigid antennas, the proposed textile antenna is non-intrusive, enhancing user safety and comfort. The denim material makes it comfortable for extended wear, reducing the risk of skin irritation. It can also withstand regular wear and tear, including stretching and bending. The presented denim-based antenna can be seamlessly integrated into clothing and accessories, making it less obtrusive and more aesthetically pleasing.

Advancements in mobile antenna design: A comprehensive literature review

This study reviews the literature on antenna design in mobile applications, analyzing research, theses, and academic papers to summarize current developments, identify gaps, and suggest future research lines. The review aims to compile the most recent findings on mobile antenna design from respected English-language journals. The study analyzes forty articles discussing both advanced and traditional antenna designs, focusing on efficiency, noise reduction, SAR compliance, size restrictions, polarization, and gain. It emphasizes the importance of innovation and multidisciplinary methods to meet the changing needs of the global communication network. The review uses keywords such as "Antenna," "Antenna Design," "Mobile Antenna," and "Mobile Antenna Design" to find relevant studies across IEEE Xplore, Scopus, Web of Science, and Google Scholar.

FBG Sensing Data Motivated Dynamic Feature Assessment of the Complicated CFRP Antenna Beam under Various Vibration Modes

Carbon fiber-reinforced polymer (CFRP) components were extensively used and current studies mainly refer to CFRP laminates. The dynamic performance of the complicated CFRP antenna beams is yet to be explored. Therefore, a sensor layout based on fiber Bragg gratings (FBGs) in series was designed to measure the dynamic response of the CFRP antenna beam, and various vibration tests (sweep frequency test, simulated long-life vibration test, shock vibration test, functional vibration test, and constant frequency vibration test) were conducted. The time and frequency domain analysis on FBG sensing signals was performed to check the vibration performance and assess the health condition of this novel CFRP structure. The results indicate that strain values reach a maximum of only 300 µε under different test conditions. The antenna beam exhibited clear vibration patterns, with the first four intrinsic frequencies identified at 44, 94.87, 107.1, and 193.45 Hz. It shows that strain distribution and vibration modes of the antenna beam can be characterized from the sensing data, and the dynamic feature can be much more accurately assessed. The FBG sensors attached on the surface of CFRP antenna beam can accurately and stably measure the dynamic response, which validates that the interfaces between optical fiber sensing elements and CFRP material have excellent interfacial bonding characteristics. The novel CFRP antenna beam exhibits the excellent dynamic performance and stability, offering the replacement of traditional steel antenna beams. The study can finally instruct the development of self-sensing CFRP antenna beams assembled with FBGs in series.

Analysis of spiral antenna for enhancing antenna-plasma coupling impedance for SST-1 tokamak

Abstract A detailed characterization of a high-power radio frequency (RF) broadband circularly polarized two-arm spiral antenna is designed to operate within the frequency range of 0.1–1.0 GHz. The impedance matching network technique is introduced to optimize its performance. The traditional spiral antenna is excited by a vertical or horizontal balun, whereas the proposed design is directly fed by a coaxial cable featuring a planar feeding section specially optimized to achieve broadband input impedance matching. The spiral antenna is designed as per the steady-state superconducting tokamak (SST-1) port space constraints. The simulated efficiency of the RF power coupling with the hydrogen plasma is ∼70 %. Through simulation, it was evident that the proposed antenna exhibited inherent resonance at 0.5 GHz with a reflection coefficient of −27.94 dB and an axial ratio is 3.39 dB respectively. The obtained outcomes unequivocally demonstrate the circular polarization of the designed antenna. Overall, the findings support the enhancement of plasma heating and current drive techniques in fusion research.

High-gain mmWave shorted rectangular ring antenna with complementary segmented-cavity backed structure

An efficient gain-enhancement technique for millimeter wave (mmWave) planar patch antennas (PPAs) using a novel slot-loaded and segmented-cavity backed structure is newly proposed in this study. By incorporating a main radiator with a rectangular slot and employing a muli-layered segemented-cavity, the proposed antenna design significantly increases antenna gain beyond conventional approaches. Unlike traditional patch antennas or those with shorting pin structures, our gain-enhanced PPA utilizes the rectangular slot to electrically expand the radiation aperture, while the addition of substrate integrated pillars acorss multiple segmented ground layers markedly improves antenna directivity. The strategric use of a segmented cavity not only facilitates flexible impedance matching but also ensures consistent performance within the n257 band, accompanied by minimal gain variation. To verify the gain enhancement from the conventional patch, the proposed antenna was fabricated with a size of 1.03 λ0 × 1.03 λ0 × 0.1 λ0 at 28 GHz. The measured 10-dB impedance bandwidth was 12.14 % with a maximum measured gain of the 11.28 dBi at 28 GHz. Compared to the measured gain of the conventional PPA with the same size, the gain was 39.6 % higher, which represents the highest gain per total antenna volume observed for a single PPA in the mmWave spectrum for high-gain applications, to the best of our knowledge.

Flexible Graphene Film-Based Antenna Sensor for Large Strain Monitoring of Steel Structures.

In the field of wireless strain monitoring, it is difficult for the traditional metal-made antenna sensor to conform well with steel structures and monitor large strain deformation. To solve this problem, this study proposes a flexible antenna strain sensor based on a ductile graphene film, which features a 6.7% elongation at break and flexibility due to the microscopic wrinkle structure and layered stacking structure of the graphene film. Because of the use of eccentric embedding in the feeding form, the sensor can be miniaturized and can simultaneously monitor strain in two directions. The sensing mechanism of the antenna is analyzed using a void model, and an antenna is designed based on operating frequencies of 3 GHz and 3.5 GHz. The embedding size is optimized using a Smith chart and impedance matching principle. Both the simulation and experimental results verify that the resonant frequency and strain magnitude are linearly inversely proportional. The experimental results show that the strain sensitivity is 1.752 kHz/με along the geometric length and 1.780 kHz/με along the width, with correlation coefficients of 0.99173 and 0.99295, respectively.

Design of dual mode antenna using CMA and broadband dual-polarized antenna for 5G networks

This article proposes a dual mode dual-polarized antenna configuration for IRNSS and fifth generation (5G) applications, operating at a frequency of 3.5 GHz based on characteristic mode analysis (CMA), and aims to provide broadband dual-polarized functionality. The original design of the antenna is a traditional patch antenna, and its dual-polarized features are determined using characteristic mode analysis. The full-wave method is used to stimulate both orthogonal modes using a 50 Ω coaxial input line at 3.5 GHz. In this design, the circular patch has been extended into an elliptical patch through a process of mode separation. The circular patch exhibits resonance at a frequency of 2.5 GHz, whereas the extended elliptical radiator demonstrates two resonance modes at 2.5 GHz and 3.5 GHz. The operational mechanism is elucidated by modal analysis and characteristic angle. This antenna operates on two different frequencies at the 2.5 GHz IRNSS band with horizontal polarization and the 3.5 GHz 5G service with vertical polarization. The maximum gain achieved with these frequency ranges is 5.31 dBi and 4.72 dBi, respectively. A ring resonator is chosen to improve the axial ratio and impedance bandwidth of the suggested prototype. The antenna's ground plane is shaped like a rectangle and features a V-shaped slot in the radiating patch. The antenna's physical footprint is 50 mm × 50 mm × 1.6 mm and an FR4 dielectric substrate serves as its foundation. Through its interaction with a PIN diode, the diode modifies the polarization of the antenna. The antenna functions as a right-handed circular polarization (RHCP), when the diode is operational. The bandwidth from 4.3 to 7.5 GHz is covered. On the other hand, it generates linear polarization (LP) between 4.2 and 5.3 GHz. The experimental antenna is evaluated and examined for its performance characteristics. The simulations are carried out utilizing the CST simulator. A prototype antenna has been manufactured and its performance has been validated against simulated findings.

Widening Multi‐Beam Scan Angle of Conventional Waveguide Lens Antennas by Increasing Focal Points for Multi‐Feed Excitations

AbstractThis paper presents an alternative approach to improve the achievable beam scan angle of a traditional multi‐beam waveguide lens antenna. Due to the focusing mechanism by manipulating the geometrical curvatures of the waveguide lens, the angular scan range is limited in the conventional waveguide lens design using dual‐focal points of excitations because the geometrical curvatures of the waveguide lens only provide two design freedoms. To overcome this limitation, a solution of treating the waveguide lens as a transmit array consisting of non‐identical elements is proposed so that each element of the antenna array can be well calibrated to improve the maximum scan angular range, where a third focus point of excitation can be created by adding another design freedom from the differentiation between non‐identical elements. Each element of this new transmitting array can be well calibrated with the help of a mathematical expression to improve the maximum angular scan range. Numerical simulations show that the proposed antenna architecture exhibits better radiation characteristics than the traditional waveguide lens antenna. Radiation characteristics are studied and compared for both types of lens antennas to validate the design concept. The proposed triple‐focal point provides a higher gain than the traditional lens antenna with fewer antenna elements. The gains of the beams at ±10°, ±20°, ±30°, and ±40° are found to be 27.78, 26.94, 26.19, and 24.04 dBi, respectively. From the comparison, it is seen that the variation in gain by the proposed triple‐focal array design is more stable than the conventional dual‐focal point design.

Next-generation antennas key enabler: Intelligent Reflecting Surfaces (IRS) technology potential to address limitations of traditional antennas

Next-generation antennas key enabler: Intelligent Reflecting Surfaces (IRS) technology potential to address limitations of traditional antennas

Structural Optimization Design of Magnetoelectric Thin-Film Antenna for Bandwidth and Radiation Enhancement.

The acoustically actuated nanomechanical magnetoelectric (ME) antennas represent a promising new technology that can significantly reduce antenna size by 1-2 orders of magnitude compared to traditional antennas. However, current ME antennas face challenges such as low antenna gain and narrow operating bandwidth, limiting their engineering applications. In this paper, we enhance the bandwidth and radiation performance of ME antennas through structural optimization, leveraging theoretical analysis and numerical simulations. Our findings indicate that optimizing the inner diameter of the ring-shaped ME antenna can elevate the average stress of the magnetic layer, leading to improved radiation performance and bandwidth compared to circular ME antennas. We establish an optimization model for the radiation performance of the ME antenna and conduct shape optimization simulations using COMSOL Multiphysics. The results of the Multiphysics field optimization align with the stress concentration theory, demonstrating a strong correlation between the radiation performance and bandwidth of the ME antenna with the average stress of the magnetic film. The resonant frequency in the thickness vibration mode is determined to be 170 MHz. Furthermore, shape optimization can enhance the bandwidth by up to 104% compared to circular ME antenna structures of the same size.

Dual-Polarized Dipole Antenna with Wideband Stable Radiation Patterns Using Artificial Magnetic Conductor Reflector.

This paper presents a wideband dual-polarized dipole antenna structure operating at 1.7-3.8 GHz (76.4%). For a traditional 4G dipole antenna that covers the band 1.71-2.69 GHz, it is difficult to maintain the satisfactory impedance matching and normal stable radiation patterns within the 5G sub-6 GHz band 3.3-3.8 GHz, mainly due to the fixed antenna height no longer being a quarter-wavelength. To solve this, a connected-ring-shaped metasurface structure is proposed and deployed to operate as an artificial magnetic conductor (AMC). As a result, stable antenna radiation patterns are obtained within the whole band 1.7-3.8 GHz. For verification, this wideband dipole antenna using AMC is implemented and tested. The measured results show that the proposed antenna has an impedance bandwidth of 80.7% (1.7-4.0 GHz). It has an average measured in-band realized gain of 7.0±1.0 dBi and a stable 70±5 half power beam width (HPBW) within the 4G/5G-sub 6GHz bands 1.71-2.69 GHz and 3.3-3.8 GHz.

A Bionic Flapping Magnetic-Dipole Resonator for ELF Cross-Medium Communication.

Extremely low-frequency (ELF) electromagnetic (EM) waves adeptly propagate in harsh cross-medium environments, overcoming rapid decay that hinders high-frequency counterparts. Traditional antennas, however, encounter challenges concerning size, efficiency, and power. Here, drawing inspiration from nature, we present a groundbreaking piezo-actuated, bionic flapping-wing magnetic-dipole resonator (BFW-MDR), operating in the electro-mechano-magnetic coupling mechanism, designed for efficient ELF EM wave transmission. The unique rigid-flexible hybrid flapping-wing structure magnifies rotation angles of anti-phase magnetic dipoles by tenfold, leading to constructive superposition of emitted magnetic fields. Consequently, the BFW-MDR exhibits a remarkable quality factor of 288 and an enhanced magnetic field emission of 514 fT at 100 meters with only 6.9 mW power consumption, surpassing traditional coil antennas by three orders of magnitude. The communication rate is doubled by the ASK+PSK modulation method. Its robust performance in cross-medium communication, even amidst various interferences, underscores its potential as a highly efficient antenna for underwater and underground applications.