Mobile Antenna Research Articles

EM Radiation Thermal Effects Simulation Study on a Realistic Female Model at Some Frequencies

The purpose of research is to develop a computer simulation based mobile phone safety testing scheme that is well suited for testing any mobile phone antenna at different communication frequencies and various realistic scenarios. It has been shown how feasible the study of realistic models is, what difficulties may occur, what effects, moments appear in the modeling process. The aim of the study is also to show the need for changes in the standard of mobile phone safety testing and to investigate the possibilities of implementing these changes. It is preferable for manufacturers to perform testing using human realistic models through numerical calculations and conduct safety compliance testing under realistic conditions to produce more realistic picture. Computer modeling gives the possibility to consider various realistic models, realistic scenarios and different tissue dielectric properties according to the frequency. It was investigated how mobile phone antenna radiation parameters (S11 reflection coefficient) change according to the various positions of the hand and fingers at standard communication 2100 MHz and 3700 MHz frequencies; were estimated Specific Absorption Rate (SAR) values in the human head and their dependence on S11 parameters were studied. Based on the obtained results, it has been shown that the preferred S11 behavior should be one of the indicators in the phone safety standards. For this, manufacturers should carry out mobile phone antenna matching/S11 parameter testing with free space.

Heat-Dissipating Mobile Antenna: A Novel Mobile Antenna Concept with Extremely Small Clearance and Integrated Heat-Dissipating Function

Heat-Dissipating Mobile Antenna: A Novel Mobile Antenna Concept with Extremely Small Clearance and Integrated Heat-Dissipating Function

Reliable and Energy-Efficient Communications in Mobile Robotic Networks by Collaborative Beamforming

For mobile robotic networks in industrial scenarios, reliable and energy-efficient communications are crucial yet challenging. Fortunately, collaborative beamforming (CB) emerges as a promising solution, which can increase the transmission gain and reduce the transmit power of robots by constructing a mobile robot-enabled virtual antenna array (MRVAA). The performance of CB is tightly related to robot positions, necessitating proper robot selection. However, robot selection may expose the network to the risk of unbalanced energy distribution, reducing network lifetime. Additionally, the mobility and variable numbers of robots require flexible and scalable robot selection algorithms. To tackle these challenges, we first formulate a multi-objective optimization problem to reduce the maximum sidelobe level (MSLL) of MRVAA while minimizing the standard deviation of the network energy distribution (SDNED) by selecting robots for CB. Then, based on distributed multi-agent learning (MARL), we propose an effective and scalable robot selection algorithm with energy considered (RoSE) to solve the problem, where difference-rewards function (DRF) and policy sharing are designed for enhancing convergence rate and policy stability. Simulation results show that the RoSE has the scalability to positions and numbers of robots. Furthermore, RoSE surpasses existing selection algorithms in network lifetime and time efficiency, while still maintaining comparable MSLL.

Simulation and Design of Three 5G Antennas

In the context of 5G networks, this paper investigates microstrip array antennas and mobile terminal MIMO array antennas. It introduces two innovative designs and, based on these, develops and fabricates a mobile terminal antenna. The first of these designs, a 4 × 4 microstrip array antenna operating in the LTE band 42 (3.4–3.6 GHz), is researched and fabricated and an innovative approach, combining embedded and coaxial feeding methods, is proposed and employed. Measurement results indicate a bandwidth of 373 MHz (3.321–3.694 GHz), achieving a relative bandwidth of 10.7%. The antenna exhibits a high gain of 12.7 dBi, with an undistorted radiation pattern, demonstrating excellent directional characteristics. The second of these designs, a “loop-slot” MIMO antenna designed for 5G mobile devices with metal frames, is investigated. By opening slots in the metal frame and integrating them into the antenna’s feeding structure, the decoupling principle is analyzed from the perspective of characteristic mode theory. This design shares resonant modes between the loop and slot antennas, allowing for the overlapping placement of the two antenna units. Experimental results confirm an isolation level exceeding 21 dB, with significantly reduced dimensions. Finally, an eight-unit MIMO antenna is designed and fabricated for 5G mobile devices with metal frames. Continuous optimization of the “loop-slot” module layout and unit spacing leads to a compact and miniaturized antenna structure. Measurement results show an isolation level exceeding 17 dB, radiation efficiency ranging from 65.8% to 73.7%, and an envelope correlation coefficient (ECC) below 0.03. Finally, an analysis of specific absorption rate (SAR) demonstrates excellent MIMO performance in terms of human body radiation exposure.

Distributed Mobile Antennas: A Novel Miniaturized Wideband Antenna Strategy to Maximize the Use of the Fragmented Spaces of the Mobile Terminals

Distributed Mobile Antennas: A Novel Miniaturized Wideband Antenna Strategy to Maximize the Use of the Fragmented Spaces of the Mobile Terminals

A Deep Learning Framework for Evaluating the Over-the-Air Performance of the Antenna in Mobile Terminals.

This study introduces RTEEMF (Real-Time Evaluation Electromagnetic Field)-PhoneAnts, a novel Deep Learning (DL) framework for the efficient evaluation of mobile phone antenna performance, addressing the time-consuming nature of traditional full-wave numerical simulations. The DL model, built on convolutional neural networks, uses the Near-field Electromagnetic Field (NEMF) distribution of a mobile phone antenna in free space to predict the Effective Isotropic Radiated Power (EIRP), Total Radiated Power (TRP), and Specific Absorption Rate (SAR) across various configurations. By converting antenna features and internal mobile phone components into near-field EMF distributions within a Huygens' box, the model simplifies its input. A dataset of 7000 mobile phone models was used for training and evaluation. The model's accuracy is validated using the Wilcoxon Signed Rank Test (WSR) for SAR and TRP, and the Feature Selection Validation Method (FSV) for EIRP. The proposed model achieves remarkable computational efficiency, approximately 2000-fold faster than full-wave simulations, and demonstrates generalization capabilities for different antenna types, various frequencies, and antenna positions. This makes it a valuable tool for practical research and development (R&D), offering a promising alternative to traditional electromagnetic field simulations. The study is publicly available on GitHub for further development and customization. Engineers can customize the model using their own datasets.

Movement patterns of a small-bodied minnow suggest nomadism in a fragmented, desert river

BackgroundUnfettered movement among habitats is crucial for fish to access patchily distributed resources and complete their life cycle, but many riverscapes in the American Southwest are fragmented by dams and dewatering. The endangered Rio Grande silvery minnow (Hybognathus amarus, RGSM) persists in a fragmented remnant of its former range (ca. 5%), and its movement ecology is understudied.MethodsWe tracked movements of hatchery-reared RGSM, tagged with passive integrated transponder tags, using stationary and mobile antennas from 2019 to 2022. We quantified probability of movement and total distance moved by RGSM released above and below a dam. We then assessed how well two prevailing riverine movement theories (i.e., restricted movement paradigm [RMP] and colonization cycle hypothesis [CCH]) explained RGSM movement patterns.ResultsWe detected 36.8% of released RGSM (n = 37,215) making at least one movement. Movements were leptokurtic and substantially greater than expected based on the RMP for both stationary (1.7–5.9 m) and mobile (30.3–77.8 m) individuals. On average, RGSM were detected at large for 75 days and moved a total of 12.2 rkm within a year. The maximum total distance moved by RGSM was 103 rkm. Similarly, we observed a multimodal distribution of detected range sizes with a mean detected range of 2.4 rkm and a maximum detected range of 78.2 rkm. We found little support for an upstream movement bias, as expected under the CCH, and most movements (74%) were directed downstream.ConclusionsOur data suggest RGSM are highly mobile, with the ability to make long-distance movements. Neither movement theory adequately described movement patterns of RGSM; instead, our findings support a nomadic movement pattern and an apparent drift paradox matching recent studies of other pelagic-broadcast spawning minnows where populations persist upstream despite experiencing downstream drift as larvae. Resolution of the drift paradox may be achieved through further, targeted studies into different aspects of the species’ life history. Quantification of RGSM movement provides crucial insights into the species’ movement ecology and may help define the appropriate scale of recovery efforts.

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.

Measurement of the electric field of mobile telephone base station antennas in Riobamba (Ecuador), to determine the specific absorption rate (SAR) in the human body

Exposure to electromagnetic and radio frequency fields generated by communication technologies such as mobile phones has raised concerns about electromagnetic pollution and its possible health effects. The objective of the study was to measure the electric field coming from cell phone base station antennas and determine through simulation in virtual anatomical models the maximum and average SAR in the whole body and in 10 g in different parts of the human body. The measurements were carried out with a selective non-ionizing electromagnetic radiation meter at 10 sites in the city of Riobamba, Ecuador. The highest maximum and average SAR for whole body was 3.045x10−7 and 3.923 x10−8 W/kg, respectively. While, at 10 g, the maximum SAR reached up to 8.52x10−9 W/kg in arms and the average SAR 2.13x10−9 W/kg in legs. All results are well below the limits established by the ICNIRP, suggesting a low risk of exposure. This work provides valuable information on the levels of exposure to electric fields from mobile telephone base stations and the results collected in this research could serve as a reference for future research, since the sampling method used could be reproduced to study the temporal variation of electric field levels in the city and conduct more comprehensive studies of SAR distribution in the human body.

Design of Miniaturized and Wideband Four-Port MIMO Antenna Pair for WiFi.

A miniaturized and wideband four-port multiple-input multiple-output (MIMO) antenna pair for Wi-Fi mobile terminals application is proposed. The proposed antenna pair consists of four multi-branch antenna elements arranged orthogonally, with an overall size of 40 × 40 × 3.5 mm3 and each antenna element size of 15.2 × 3.5 mm × 0.8 mm3. The performance of the proposed antenna shows the advantages of a wide frequency band, low mutual coupling, high efficiency, and a compact structure. The wideband characteristics of the antenna elements are achieved through multi-mode resonance. The suppression of coupling is accomplished by strategically positioning the four compact antenna elements to ensure their maximum radiation directions are orthogonal, thus eliminating the need for an additional decoupling structure. In this paper, the proposed antenna is optimized in terms of the parameters then simulated and measured. The simulated results illustrate that an impedance bandwidth of the antenna is about 15% (5.06~5.88 GHz) with S11 < -10 dB, excellent port isolation exceeds 20 dB between all ports, a high radiation efficiency ranges from 51.2% to 89.9%, the maximum gain is 4.5 dBi, and the ECCs are less than 0.04. The measured results show that the -10 dB impedance bandwidth of the antenna is about 13% (5.13~5.80 GHz), the isolation between the antenna elements is better than 21 dB, the radiation efficiency ranges from 51.8% to 92.3%, the maximum gain is 5.3 dBi, and the ECCs are less than 0.05. The proposed four-port MIMO antenna works on the 5G LTE band 46 and Wi-Fi 6E operating bands. As a mobile terminal antenna, the proposed design scheme demonstrates excellent performance and applicability, fulfilling the requirements for 5G mobile terminal applications.

Crown Ether Copolymerized Polyimide Film: Enhanced Mechanical, Thermal Properties and Low Dielectric Constant under High Frequency.

Polymer materials with a low dielectric constant and low dielectric loss have the potential to be applied to high-frequency signal transmissions, such as mobile phone antennas and millimeter wave radars. Two types of diamines, 4,4'-diamino-p-tetraphenyl (DPT) and crown ether diamine (CED), were prepared for ternary copolymerization with BPDA in this study. Cross-links with molecular chains were formed, increasing molecular chain distance by utilizing rings of CED. The MPI films exhibit a good thermal performance with the increase in CED addition, with Tg > 380 °C and CTE from -4 × 10-6 K-1 to 5 × 10-6 K-1. The Young's modulus can reach 8.6 GPa, and the tensile strength is above 200 MPa when 5% and 7% CED are introduced. These MPI films exhibit good mechanical performances. The dielectric constant of PI-10% film can go as low as 3.17. Meanwhile, the relationship between dielectric properties and molecular structure has been demonstrated by Molecular Simulation (MS). PI molecules are separated by low dielectric groups, resulting in a decrease in the dielectric constant.

Radiation-Based Figure of Merit for Environmental Sensitivity Analysis of Mobile Phone Antennas: A standard tool to evaluate different antenna solutions

The performance of mobile phone antennas is strongly dependent on their environment. However, in the literature, there is no standard criterion to judge this environmental sensitivity. In this work, first, an elaborate figure of merit (FOM) is introduced based on the radiation characteristics of antennas. Then, characteristic modes (CMs) are employed to provide another representation of this FOM. This technique is able to deliver an in-depth understanding of the effect of the environment on the radiating modes of an antenna, which are strongly related to the sensitivity. This perception opens the possibility for designers to achieve less-sensitive antennas. To demonstrate the applicability of the proposed FOM, it is applied to a range of mobile phone antennas available in the literature.

Far-Field Estimation Method of Antennas Above Conductive Plane Using a Partially Spherical Near-Field

For evaluating the practical performance of land mobile communication antennas via near-field measurement, it is essential to measure the electromagnetic field, including the housing in which the antennas are mounted. When measuring a heavy housing, scattered waves from the supporting turntable for the antenna under test (AUT) disturb the electromagnetic field. A technique for eliminating the influence of scattered waves is required to evaluate the abnormal AUT radiation performance. This paper proposes a method for estimating the far-field when the antenna exists above an infinite conductive plane, using partially spherical near-field measurements that include the turntable. The proposed method estimates the far-field by combining the equivalent source reconstruction and the far-field estimation with the reflection coefficient method. In the proposed method, the equivalent source distribution surrounding an AUT is reconstructed from a partially spherical near-field to remove the effects of the turntable. Through numerical calculations and experiments, this paper shows that the proposed method can estimate the far-field pattern above an infinite conductive plane, with arbitrary electric constants from a partially spherical near-field. The far-field estimation error is less than -20 dB when the upper hemispherical near-field can be obtained.

Applications of 5G technology in flexible electronics

As an emerging field in the industry, flexible electronics not only integrates technologies in fields such as electronic circuits, materials, and flat displays, but also spans industries such as semiconductors, materials, chemicals, and printed circuit boards. Its application importance in various fields such as information, energy, healthcare, and manufacturing are increasingly prominent. The main topic of this article is the implementation of 5G technology in the flexible electronics industry. To begin with, this article presents the traits of flexible electronics. Secondly, it stated the development of 5G and introduced its characteristics. The result shows that 5G is not only an air interface technology with higher rates, larger bandwidth, and stronger capabilities, but also an intelligent network for user experience and business applications. Then, combined with 5G and flexible electronics, they are applied in three aspects: mobile antennas, intelligent equipment, and remote medicine. Finally, the current problems and future prospects in the fields of flexible electronics and 5G were summarized. Currently, it faces challenges such as signal interference and power consumption due to the unique characteristics of flexible materials. And in the future, 5G can potentially enhance the performance of flexible electronics, leading to the creation of new products and services in various industries.

Optimization of the Thermally Conductive Low-k Polymer Dielectrics Based on Multisource Free-Volume Effects.

Polymers/polymer matrix composites possessing low dielectric constants (low-k polymer dielectrics) contribute to the advance of electronics, for instance, microprocessor chips, mobile phone antennas, and data communication terminals. However, the intrinsic long-chain structural characteristic results in poor thermal conductivities, which draw heat accumulation and undermine the outstanding low-k performance of polymers. Herein, multisource free-volume effects that combine two novel kinds of extra free volume with the known in-cage free volume of polyhedral oligomeric silsesquioxanes (POSSs) are discussed to reduce the capacity for dielectric constant reduction. The multisource free-volume effects of POSSs are associated with the thermal conductive network formed by the hexagonal boron nitride (BN) in the polymer matrix. The results show a decent balance between low-k performance (dielectric constant is 2.08 at 1 MHz and 1.98 at 10 GHz) and thermal conductivity (0.555 W m-1 K-1, 4.91 times the matrix). The results provide a new idea to maximize the free-volume effects of POSSs to optimize dielectric properties together with other desired performances for the dielectrics.

Compact triple band notched UWB MIMO antenna with integrated GSM

SummaryThis paper introduces an innovative four‐element Ultra‐wideband (UWB) MIMO structure featuring an integrated global system for mobile (GSM) antenna with the ability to achieve dual and triple band‐notch capabilities. The antenna's distinctiveness is achieved through the utilization of four directional meandered line shaping decoupling structures (MLSDS), an orthogonal arrangement, and multi‐slot techniques. The incorporation of orthogonal separation alongside four directional MLSDS significantly reduces the mutual interference between radiating elements. By placing MLSDS on both sides of the substrate, effective coverage of the GSM band is achieved. The development of the MIMO structure unfolds through four distinct phases. The initial stage lacks MLSDS, while the second stage incorporates MLSDS. The third and fourth stages respectively introduce MLSDS with dual and triple notch characteristics. The presence of MLSDS enhances the antenna's impedance bandwidth (IBW). The intended notches are tailored to address interference from bands like Band n41, WLAN, and X‐band. Furthermore, the proposed antenna has undergone simulation, measurement, and comparative analysis with existing models, focusing on diversity performance metrics. The results reveal its exceptional diversity performance, positioning it as a potential choice for creating a portable UWB‐MIMO system.

Design of a Deployable Broadband Mesh Reflector Antenna for a SIGINT Satellite System Considering Surface Shape Deformation.

In this paper, we propose a deployable broadband mesh reflector antenna for use in signals intelligence (SIGINT) satellite systems, considering performance degradation due to shape deformation. To maximize gain by increasing the diameter of the reflector while reducing the weight of the antenna, the reflector of the antenna is designed using lightweight silver-coated Teflon mesh. The mesh reflectors are typically expanded by tension to maintain their parabolic structure; thus, shape deformation cannot be avoided. This shape deformation results in shape differences between the surface of the mesh reflector and the ideal parabolic reflector, thus resulting in the degradation of the performance of the mesh reflector antenna. To observe this degradation, we analyze antenna performance according to the number of arms, the number of joints, the feed distance, and the distance from the reflector center to each joint. The performance of the mesh reflector antenna is examined using an effective lossy conducting surface (ELCS) that has the same reflectivity as the silver-coated Teflon mesh to reduce simulation time and computing resources. The designed silver-coated Teflon mesh reflector and the double-ridged feed antenna are fabricated, and the bore-sight gain is measured using the three-antenna method. The measured bore-sight gain of the proposed antenna is 31.6 dBi at 10 GHz, and the measured and simulated results show an average difference of 3.28 dB from 2 GHz to 18 GHz. The proposed deployable mesh reflector antenna can be used in a variety of applications where small stowed volume is required for mobility, such as mobile high-gain antennas as well as satellite antenna systems. Through this study, we demonstrate that shape deformation of the mesh reflector surface significantly affects the performance of reflector antennas.

Modeling of kinematic characteristics of the line of sight of a mobile antenna of a spacecraft when it is pointed at an information reception point

Modeling of kinematic characteristics of the line of sight of a mobile antenna of a spacecraft when it is pointed at an information reception point

Modeling of kinematic characteristics of a mobile antenna of a spacecraft in a two-stage pivoting device

Modeling of kinematic characteristics of a mobile antenna of a spacecraft in a two-stage pivoting device

Is there an effect of electromagnetic waves from base stations on the breeding success of Ciconia ciconia ciconia in Algeria?

New nest supports used by the white stork Ciconia ciconia ciconia (Linnaeus, 1775) are mobile phone network relay antennas, which are not without danger because they emit electromagnetic waves that can have a major, although insidious, impact on the species. The aim of this study is to assess the effects of electromagnetic waves from mobile phone network base stations on white stork reproduction. We monitored the breeding phenology of the storks as a function of the distance of their nests from the base stations over 2 consecutive seasons, 2020 and 2021. The work took place in the North-East of Algeria, in Annaba and El-Tarf provinces. The nests were counted and divided into 3 distinct groups. The first is located on the relay antennae, the second less than 200 m and the third more than 300 m from the antennae. We calculated nest occupancy, number of young in the nest and number of nests without young. The results show that nests located directly on base stations have a reduced clutch size, not exceeding two storks and a low reproductive success since the majority of nests (51.9%) remained without young. The number of young storks tends to increase in nests far from base stations. Broods with 3 and 4 young are generally those located more than 300 m from relay antennas.