Antenna Position Research Articles

Control system design for azimuth position of earth station antennas

Smart earth station antennas have been used for several decades in many applications, from satellite communications to space object detection and tracking. The accuracy of the azimuth position for such antennas plays a crucial role in most steerable ground station antennas. Satellite tracking and space object detection demand precise tracking capabilities from the Earth. Several methods and techniques have been developed and used in industry to control the directions of ground station antennas, including the azimuth position. The challenge of azimuth tracking is increasing with the demand for full-sky coverage and with the exponential increase in space objects, including man-made satellites and operational and nonoperational objects; thus, providing accurate tracking is a key technology that demands continuous enhancement and development. This article presents the use of a PID-proportional-integral-derivative controller, a slide mode controller and a fractional order PID controller. It also introduces a new methodology based on model predictive control (MPC). The manuscript provides the core design for each of these controllers and provides insight into the performance of each controller even in the presence of disturbance. The camel optimization algorithm (COA) was used to obtain the optimal design parameters of each controller in the considered scenarios.

Location of 5G base station antenna in substation taking into account path loss and RF radiation

Aiming at the engineering problem that 5G base station antenna is difficult to locate efficiently in complex electromagnetic environment, a two-stage positioning method of 5G base station antenna substation is proposed, which considers signal path loss and antenna RF radiation. Firstly, the path loss solution model of the 5G base station antenna signal in the substation is established, and the RF radiation solution model generated by the coupling excitation of 5G high-frequency electromagnetic wave and the metal shell of the electrical equipment is constructed based on the big element physical optics method. Secondly, combining the advantages of particle swarm optimization (PSO) and interior point algorithm, the antenna positioning method considering path loss and RF radiation is constructed. Among them, in the first stage, the minimum loss of 5G signal path in the substation is taken as the goal, and the antenna stations in the substation are searched globally to get the optimal pre-selected position. In the second stage, the antenna position is calibrated according to the pre-selected position, so that the interference of RF radiation is minimized, and the final position is output. Finally, a 500 kV 5G substation in Henan Province was taken as the simulation object. Compared with the original scheme, the simulation results ensured the minimum 5G path loss in the substation and took into account the electromagnetic compatibility of the equipment in the substation. The effectiveness of the location strategy for maintaining the safe operation of the substation is verified, and it can provide a reference for the 5G base station antenna positioning project of the substation.

Методика обработки сигналов, позволяющая уменьшить погрешности измерений бистатических характеристик рассеяния образцов материалов

In this paper a signal processing technique for bistatic measurements of the reflection coefficient of flat material samples is presented. This technique is based on comparing the reflected signal from the object under study and the background signal in the time domain. The use of this technique makes it possible to increase the accuracy of measurements of the characteristics of bistatic scattering of objects with a small amplitude of the reflected wave. This technique allows us to offset for the measurement error caused by the inaccuracy of antenna positioning and significantly reduce the measurement error caused by the interaction of antennas with each other at large bistatic angles. The reflection coefficient of the material sample was measured. The obtained results were processed by vector subtraction, time domain and using the developed technique. It was shown that the use of this technique allows one to increase the accuracy of measuring the reflectance of the material. This technique reduces the error in determining the minimum value of the reflection coefficient and the angle at which this minimum is achieved. The most effective is to use background synthesis and time domain together.

Movable Antenna Empowered Downlink NOMA Systems: Power Allocation and Antenna Position Optimization

Movable Antenna Empowered Downlink NOMA Systems: Power Allocation and Antenna Position Optimization

Compact Ultra-Wide Band Two Element Vivaldi Non-uniform Slot MIMO Antenna for Body-Centric Applications

This work presents a novel compact two-port Vivaldi Non-uniform Slot MIMO Antenna (VNSMA) to overcome the challenges of traditional ultra-wideband (UWB) antennas, such as large size, limited bandwidth (BW), high mutual coupling, and suboptimal performance in wearable devices. Designed based on Vivaldi non-uniform slot profile antenna (VNSPA) theory, this antenna offers superior performance metrics and significantly advances wearable antenna technology. The novelty of this work is investigating different positions for the two compact UWB VNSA to get better performance with smaller sizes, wider impedance matching BW, and lower mutual coupling (MC) where side by side at an angle of 180ᵒ is determined to be the best configuration. Detailed parametric studies were performed on this configuration for better performance, where the MC was further reduced by etching the ground plane with a vertical slot between the two antennas and L slots around the Microstrip to Slot (M/S) transition, respectively. Furthermore, BW and gain enhancements were obtained by etching exponential tapered and triangular slots at its two edges. Using the Finite Integration Technique (FIT), Computer Simulation Technology (CST) software is used for the simulations in this work. The VNSMA is tested on a CST Gustav human phantom and gives excellent results with low specific absorption rate (SAR) values at several UWB frequencies. The proposed VNSMA provides good, measured outcomes of S11 < -11.08 dB with wide BW of 12.5 GHz (2.33–14.83 GHz) covering high isolation of -23 dB (for most of frequency band), moderate-high gain of 5.89 dBi, radiation efficiency of 66-90%, low Envelope Correlation Coefficient (ECC) of 0.002 and high diversity gain (DG) of 9.99 dBi, stable radiation patterns, and average group delay of 1.2 ns. This innovative design, which optimizes antenna positioning and incorporates ground plane modifications, achieves remarkable improvements in BW, which covers multiple bands, including WLAN (2.4–2.485 GHz), X-band (8-12 GHz), and part of Ku band (12-18 GHz). The findings demonstrate the antenna's potential for various high-resolution microwave imaging applications, particularly in medical diagnostics like breast and brain cancer detection, showcasing its impact in wearable technology and healthcare.

UAV data link anti-interference via SLHS-SVM-AdaBoost algorithm: Classification prediction and route planning

The ability to predict the anti-interference communications performance of unmanned aerial vehicle (UAV) data links is critical for intelligent route planning of UAVs in real combat scenarios. Previous research in this area has encountered several limitations: Classifiers exhibit low training efficiency, their precision is notably reduced when dealing with imbalanced samples, and they cannot be applied to the condition where the UAV’s flight altitude and the antenna bearing vary. This paper proposes the sequential Latin hypercube sampling (SLHS)-support vector machine (SVM)-AdaBoost algorithm, which enhances the training efficiency of the base classifier and circumvents local optima during the search process through SLHS optimization. Additionally, it mitigates the bottleneck of sample imbalance by adjusting the sample weight distribution using the AdaBoost algorithm. Through comparison, the modeling efficiency, prediction accuracy on the test set, and macro-averaged values of Precision, Recall, and F1-score for SLHS-SVM-AdaBoost are improved by 22.7%, 5.7%, 36.0%, 25.0%, and 34.2%, respectively, compared with Grid-SVM. Additionally, these values are improved by 22.2%, 2.1%, 11.3%, 2.8%, and 7.4%, respectively, compared with particle swarm optimization (PSO)-SVM-AdaBoost. Combining Latin hypercube sampling with the SLHS-SVM-AdaBoost algorithm, the classification prediction model of anti-interference performance of UAV data links, which took factors like three-dimensional space position of UAV and antenna bearing into consideration, is established and used to assess the safety of the classical flying path and optimize the flying route. It was found that the risk of loss of communications could not be completely avoided by adjusting the flying altitude based on the classical path, and that intelligent path planning based on the classification prediction model of anti-interference performance can realize complete avoidance of being interfered while reducing the route length by at least 2.3%, thus benefiting both safety and operation efficiency.

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.

تقييم أداء هوائي المايكروسترب لتقليل إمتصاص الموجات الكهرومغناطيسية في األنسجة البشرية في نطاقات 5جي

The absorption of electromagnetic waves emitted by wireless devices in human tissues is quantified by the Specific Absorption Rate (SAR) measured for 1g or 10g of body tissues. The primary objective of this research is to identify an effective shield material that can minimize the impact and potential harm of electromagnetic waves on human tissues. The study involves the design of a single radiator Microstrip antenna operating at 28 GHz and the modelling of human tissue layers. SAR calculations for 1g of body tissues are performed based on the distance between the antenna and the head model. To evaluate the influence of antenna position on the head model, SAR calculations are conducted using two different approaches. In the first approach, the head model is positioned on the patch radiator side, while in the second approach, it is placed on the ground plane side. The aim is to determine which configuration yields lower SAR values. Furthermore, SAR calculations are reanalysed by incorporating shielding materials onto the Microstrip antenna. Three different absorbed materials are used as shields, and their impact on SAR reduction and radiation parameters of the Microstrip antenna are evaluated. The objective is to identify the shield material that achieves the highest SAR reduction while minimally affecting the radiation parameters of the antenna.

Fast Optimization of the Installation Position of 5G-R Antenna on the Train Roof

Fast Optimization of the Installation Position of 5G-R Antenna on the Train Roof

Near-field DOA estimation oriented sparse array design via symmetric augmentation of three ULAs

A symmetric sparse array, via symmetric augmentation of three (SAT) uniform linear subarrays, has been designed for direction of arrival (DOA) estimation of uncorrelated near-field or coexisted near-field and far-field narrowband source signals. With an explicit design of the subarray structures and positions, this SAT array 1) involves only two closely spaced antenna pairs (with quarter-wavelength spacing); 2) has a large uniform degree of freedom (uDOF) and difference co-array; 3) can have either even or odd number of antennas; and 4) has closed form expressions for antenna positions, uDOF and weight functions. Simulation results show that the SAT array is superior to the current symmetric sparse arrays in both antenna mutual coupling and consecutive virtual aperture.

Polarization-insensitive, wideband reflective metasurface generating orbital angular momentum vortex beam

In this paper, a low-profile polarization-insensitive reflective metasurface is proposed to generate high gain and wideband orbital angular momentum (OAM) in X-band (in the frequency range of 8−12GHz). By adjusting a subwavelength pseudo-screw-shaped meta-atom’s size the required phase compensation has been achieved for designing a reflectarray antenna at 10GHz. The theoretical analyses and simulation results confirm that the proposed structure can effectively generate the first-, second-, third-, and fourth-order OAM vortex beams at the operating frequency. To verify the bandwidth of the suggested metasurface, the structure is implemented for first-order OAM mode generation at various frequencies. The outcomes of investigations show the OAM operational bandwidth and 1.5-dB gain bandwidth are attained to be 40 %, and 27.5 %, respectively. Meanwhile, approximately 14.35 % reflection efficiency was procured for the overall design at the operating frequency of 10GHz. The numerical aperture of the reflectarray metasurface is also conceptually defined and calculated for varying positions of the center-feed antenna. The admitted performance and substantial characteristics of the proposed OAM reflectarray antenna may make it a useful candidate for radar imaging and detection applications as well as broadband microwave communications.

IoT Based Antenna Positioning System

An IOT-based antenna’s position system aimed at optimizing connectivity. Through IoT-enabled actuators, the system enables remote adjustment of antenna orientation, managed by a central control unit. Real-time monitoring ensures accurate alignment for optimal signal reception, enhancing communication reliability. Key advantages include remote accessibility, allowing users to control antennas from anywhere with internet connectivity, and scalability, facilitating seamless integration into existing infrastructure. By leveraging IoT technology, the system empowers users with enhanced control over wireless communication networks, offering efficient and reliable antenna positioning solutions across diverse applications.

An efficient position optimization method based on improved genetic algorithm and machine learning for sparse array

Sparse array antennas are significant in communication and radar systems due to the advantages of high resolution, low complexity, and immunity to interference. In this letter, a novel array synthesis method based on an improved genetic algorithm (IGA) is proposed to optimize the antenna position in the sparse array. Different from the traditional generic methods with high computational complexity, a method combined with Gaussian process regression (GPR) prediction is proposed to optimize the antenna position with low computational complexity. The proposed method can minimize the peak sidelobe level (PSLL) during the beam scanning procedures. Moreover, the minimum antenna spacing constraint is also considered to ensure a physically achievable solution. Simulation results show that the proposed method can achieve a lower PSLL with fewer iterations and provide a global optimization solution for large array synthesis compared with existing methods. Furthermore, a prototype of the sparse array principle optimized by IGA is designed. Measurement results indicate that the optimized sparse array has good synthesis performance in high frequency.

Antenna Positioning and Beamforming Design for Fluid Antenna-Assisted Multi-User Downlink Communications

Antenna Positioning and Beamforming Design for Fluid Antenna-Assisted Multi-User Downlink Communications

Optimizing Antenna Positioning for Enhanced Wireless Coverage: A Genetic Algorithm Approach.

The precise placement of antennas is essential to ensure effective coverage, service quality, and network capacity in wireless communications, particularly given the exponential growth of mobile connectivity. The antenna positioning problem (APP) has evolved from theoretical approaches to practical solutions employing advanced algorithms, such as evolutionary algorithms. This study focuses on developing innovative web tools harnessing genetic algorithms to optimize antenna positioning, starting from propagation loss calculations. To achieve this, seven empirical models were reviewed and integrated into an antenna positioning web tool. Results demonstrate that, with minimal configuration and careful model selection, a detailed analysis of antenna positioning in any area is feasible. The tool was developed using Java 17 and TypeScript 5.1.6, utilizing the JMetal framework to apply genetic algorithms, and features a React-based web interface facilitating application integration. For future research, consideration is given to implementing a server capable of analyzing the environment based on specific area selection, thereby enhancing the precision and objectivity of antenna positioning analysis.

Simulating VLBI observations to BeiDou and Galileo satellites in L-band for frame ties

Abstract Using the very long baseline interferometry (VLBI) technique to observe Earth-orbiting satellites is a topic of increasing interest for the establishment of frame ties. We present a simulation study on VLBI observations to BeiDou and Galileo satellites in L-band to investigate the accuracy of inter-technique frame ties between VLBI and global navigation satellite system (GNSS). We employ a global network of 16 antennas equipped with dedicated L-band receivers capable of observing BeiDou’s B1 and B3 navigation signals and Galileo’s E1 and E6 navigation signals. Through extensive Monte Carlo simulations, we simulate 24-h sessions to determine the optimal ratio of satellite to quasar scans. The optimal schedule uses about 80–90% satellite sources. We find that the 10–20% observations of quasar sources improve the estimation of the troposphere and, consequently, the estimation of the antenna position. Combining the normal equations from seven 24-h sessions, we derive a 7-day solution. The average antenna position repeatability is 7.3 mm. We identify the limitations of the results as the tropospheric turbulence, inaccuracies in the satellite orbit determination, and the lack of a more homogeneously distributed global network. This simulation study supports the understanding in the topic of building a frame tie using VLBI observations to GNSS satellites.

MR-guided percutaneous microwave coagulation of small breast tumors

BackgroundTo evaluate the technical success and patient safety of magnetic resonance-guided percutaneous microwave coagulation (MR-guided PMC) for breast malignancies.MethodsFrom May 2018 to December 2019, 26 patients with breast tumors measuring 2 cm or less were recruited to participate in a prospective, single-institution clinical study. The primary endpoint of this study was the evaluation of treatment efficacy for each patient. Histochemical staining with α-nicotinamide adenine dinucleotide and reduced (NADH)-diaphorase was used to determine cell viability following and efficacy of PMC. The complications and self-reported sensations from all patients during and after ablation were also assessed. The technical success of the PMC procedure was defined when the area of the NADH-diaphorase negative region fully covered the hematoxylin–eosin (H&E) staining region in the tumor.ResultsAll patients had a complete response to ablation with no residual carcinoma on histopathological specimen. The mean energy, ablation duration, and procedure duration per tumor were 36.0 ± 4.2 kJ, 252.9 ± 30.9 S, and 104.2 ± 13.5 min, respectively. During the ablation, 14 patients underwent prolonged ablation time, and 1 patient required adjusting of the antenna position. Eleven patients had feelings of subtle heat or swelling, and 3 patients experienced slight pain. After ablation, one patient took two painkillers because of moderate pain, and no patients had postoperative oozing or other complications after PMC. Induration around the ablation area appeared in 16 patients.ConclusionMR-guided PMC of small breast tumors is feasible and could be applied in clinical practice in the future.Critical relevance statementMR-guided PMC of small breast tumors is feasible and could be applied in clinical practice in the future.Key points• MR-guided PMC of small breast tumors is feasible.• PMC was successfully performed for all patients.• All patients were satisfied with the final cosmetic result.Graphical

Self-steering Yagi-Uda antenna positioning system for television

The aim of this study is to develop a prototype that automatically improves the position of a Yagi-Uda antenna using a microcontroller and to illustrate its radiation pattern through the use of MATLAB&lt;sup&gt;®&lt;/sup&gt;. This study is intended for students and professors in the electronics engineering field. This served as their educational materials for teaching antenna system principles and theories. Developmental and experimental methods were used to achieve the objectives. The materials and components generally used in this study are a Yagi-Uda antenna, stepper motor, Arduino Uno, L293D motor shield, USB TV stick tuner, slotted optocoupler, ADS1115, coax cable splitter, speaker stand, and timing belt. The statistical tool used in this study was a Z-test to find out if the experiment results were significant. In testing the effectiveness of the automatic antenna system, the TV display in every increment of 1.8° was taken. It was the basis for the effectiveness of the study. At 5% α/2 level (1.96), the computed z value is 1.76, which is less than 1.96. Therefore, there is no significant difference between the picture quality of the TV display at every angle and the desired angle with maximum reception of the signal with the integration of MATLAB&lt;sup&gt;®&lt;/sup&gt;.

Real time AIS tracking system for fishermen using microcontroller-based approach

Fishing activities in the waters of Banyuwangi are relatively intense. Local fishermen often venture 50 nautical miles from the coastline using small boats. These boats are lacking adequate communication and navigation equipment, causing difficulties in obtaining assistance during emergencies. This study aims to develop an Automatic Identification System (AIS) device to be installed on fishing boats. The AIS device developed for this research incorporates the STM32F4 microcontroller, CMX7032 Evaluation Board, VHF Antenna, and Global Positioning System (GPS) as its main components. The integration and configuration of each component will be elaborated in this paper. Performance testing has yielded promising results, as the AIS device was capable of transmitting data up to 10 nautical miles from the Base Station. Utilization of AIS technology would enhance safety and communication among fishermen. Through careful integration and configuration of these components, the AIS device effectively ensures that the fishermen’s positions are accurately tracked and communicated. The successful development and testing of this device underscore its potential to bridge the communication gap, offering timely assistance and enhancing the overall safety of these seafarers.

Analysis and modeling of radio propagation fading characteristics in tunnel construction

With the development of underground rail transit, the concept of intelligent tunnel construction has been proposed and promoted. High-quality networking during tunnel construction is a prerequisite for this, making it highly urgent to establish networking during tunnel construction. When studying intra-tunnel networking, it is necessary to consider the propagation characteristics of radio waves in the tunnel. In this paper, according to the actual needs of engineering in tunnel construction and the characteristics of tunnel scenes, an improved ray tracing method is proposed, which considers the type and installation position of antennas, transceiver frequency band and power in channel modeling, and proposes a field strength calculation method under different coordinate systems according to the characteristics of straight and curved segments during tunnel construction. In addition, the propagation characteristics of radio waves in dynamic tunnel construction scenarios are quantitatively analyzed. In this paper, by establishing antenna diagram, two-dimensional and three-dimensional models of tunnels, the computer simulation method is applied to compare with the improved algorithm, and the results have good consistency, in addition, the improved algorithm does not require a lot of modeling work in the early stage, and has high applicability and portability. Not only that, this paper also makes actual measurements of the subway under construction in Zhengzhou, China in different scenarios, and verifies the effectiveness of the method.