Vehicle Antenna Research Articles

Research on the impact of train speed on the uplink performance of balise transmission system

Abstract In the CTCS system, the balise plays an important role in supporting the normal operation of trains. Based on this, this article studies the performance of the uplink of the balise transmission system under different speed conditions from three perspectives: theory, simulation, and measurement. Based on an in-depth analysis of the energy and data transmission process between the vehicle antenna and the ground balise, relevant electromagnetic theoretical models such as the input and output characteristics of the balise and the antenna magnetic field distribution are established. An electromagnetic field model of the balise transmission system is established using Maxwell software, and the simulation results are obtained. An experimental environment is built using responder products and the simulation results are analyzed. Methods are explored to improve the adaptability of responder transmission systems under high-speed operating conditions.

A multi‐objective optimization approach for beam pattern synthesis ofUAVvirtual rectangular antenna array

AbstractVirtual antenna array (VAA) formed by unmanned aerial vehicle (UAV) antenna units using collaborative beamforming (CB) technology plays an important role in the air communication system, and can be used in radar, military, disaster rescue and other places. However, there are still some issues with the beam pattern formed by this method, such as high sidelobe level (SLL), high cost and low efficiency. In this article, each UAV carries an omnidirectional antenna unit, and a large number of UAVs form a UAV virtual rectangular antenna array (UVRAA) to communicate with the ground base station (BS). We formulate an overhead minimization and efficient communication multi‐objective optimization problem (OMECMOP) which jointly optimize the excitation current weights of the UVRAA and reduce the number of UAVs in operation to improve the beam pattern, enhance the communication efficiency and decrease the overhead of UVRAA. In addition, we also propose an improved multi‐objective multi‐verse optimization algorithm based on the inverse decline curve type (ISDT‐MOMVO) which introduces a strategy optimization initialization solution with quasi‐opposition based learning (QBL) and a hybrid solution updating operators to solve the OMECMOP. The simulation results show that compared with other traditional swarm intelligence (SI) optimization algorithms the ISDT‐MOMVO algorithm produces better beam pattern and the thinning rate can reach 50%.

A Null-Filled Axisymmetric Secant-Square-Shaped Beam Antenna for Unmanned Aerial Vehicles

In this letter, an antenna with a null-filled axisymmetric secant-square-shaped beam for the unmanned aerial vehicle (UAV) is proposed. The proposed antenna consists of four monopoles with sequentially rotated feed (SRF) and a coupling-fed grooved circular patch. The radiation power ratio of the monopoles and the patch is used to shape the axisymmetric beam. The effect of the ground is also investigated to operate positively on beam shaping. A prototype was fabricated to validate the method and the performance of the proposed antenna. The gain curves of the proposed antenna coincide well with the secant-squared (sec <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) curve from θ = 0° to θ = 60° in all azimuthal angles with root mean square error (RMSE) below 1.35 dB in 5.5 GHz - 5.7 GHz.

Application of Automobile Antenna Simulation in Experimental Teaching based on CST

In this paper, it is proposed to construct electromagnetic compatibility of vehicle antenna in experimental teaching. Three types of vehicle antenna models are adopted, and full-wave electromagnetic simulation software CST is adopted to better show the outstanding significance of electromagnetic simulation software to assist experimental teaching, so as to better understand the application of vehicle antenna simulation in experimental teaching.

Analysis and Design of Filtering Series-Feed Omni-Directional Antenna for V2X Application

In general, the vehicle-to-everything (V2X) series-feed antenna excites the spurious mode radiation in the adjacent bands and thus causes the strong mutual coupling between the vehicle antennas. To solve this problem, this article proposes a method to realize a filtering series-feed V2X antenna. This antenna consists of two radiators connected to a double-sided parallel strip line (DSPSL). The DSPSL operates as the series-feed structure and the first resonator. The radiators function as the second resonator. An equivalent filtering network is analyzed and derived. Then, based on the filter synthesis, the initial design parameters are obtained to realize a second-order bandpass response. However, the synthesis method only involves <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11}$ </tex-math></inline-formula> and efficiency ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{21}$ </tex-math></inline-formula> ). The radiation performances are not concerned and satisfied. To solve this problem, the antenna currents are manipulated to generate the taper exciting. Thus, the upper sidelobe and the gain are improved. Moreover, to further enhance the out-of-band suppression level, three radiation zeros are generated by manipulating the current distribution on the DSPSL. The fabrication prototype demonstrates that the out-of-band suppression of the proposed antenna is better than 8.8 dB, which significantly reduces the mutual coupling.

Spherical near-field measurement of the offset vehicle antenna mounted on a vehicle

For the vehicle antenna measurement mounting on a vehicle, the offset mounting of the antenna will increase the maximum spherical wave expansion modes, with the increasing calculation time and the increasing risk of introducing environmental reflection noise. Therefore, basing on the matrix form of the traditional spherical wave expansion (TSWE) algorithm, this paper introduces the offset spherical wave expansion (OSWE) algorithm of the offset mounting antenna under test (AUT) aiming to decrease the maximum modes, shorten the calculation time and reduce the environmental noise with the method of spherical wave expansion. Taking LTE antenna and GPS antenna as examples, this paper analyzes the improved performance of OSWE algorithm comparing with TSWE algorithm on the vehicle antenna mounting on a vehicle, as well as the parameters like equivalent noise level (ENL), omnidirectional standard deviation (σ).

Design of a 5G Sub-6 GHz Vehicular Cellular Antenna Element with Consistent Radiation Pattern Using Characteristic Mode Analysis.

A cellular 5G sub-6 GHz vehicle antenna design with a consistent radiation pattern across the frequency bands in 0.617-5 GHz is demonstrated via characteristic mode analysis. The design focuses on maintaining monopole first-order mode radiation pattern over cellular frequency bands and avoiding higher-order modes out of the operational frequency bands to provide optimal performance for automotive requirements. Rather than using an empirical design method, the design procedure in this paper uses the calculated modal significance, characteristic current, modal radiation pattern, and reflection coefficient to define the antenna structure dimensions. The proposed design was simulated, a prototype was measured, and the performance was evaluated on a 1-m ground plane. The antenna has perfect omnidirectionality with a high and stable gain across the frequency range in the 30° area above the horizon.

Joint power control and multiple antennas optimization for reducing receiver blocking in dense VANETs

The dynamic topology of vehicular ad hoc networks (VANETs) has a significant impact on the transmission and reception of data. It will cause receiver blocking due to the increase in the number of vehicles on the road and the rapid change of network topology. How to reduce the blocking and improve the reliability of data transmission is still a challenging problem. In this paper, we first propose a joint distributed power control and multiple antennas (DPC-MA) scheme, which can minimize blocking and simultaneously improve throughput. Moreover, it works well with an increased number of vehicles. Then we build an optimization model to select the optimal transmission power and number of antennas for vehicles based on their neighborhood relationships. The formulated problem is a mixed-integer nonlinear programming problem (MINLP), which is NP-hard and usually has no feasible solution. To solve this problem, we propose a low-complexity efficient algorithm using Lagrangian duality, which decomposes the original problem into a series of sub-problems and solves them iteratively using the fixed-point iterative algorithm and sub-gradient method. Simulation results show that our proposed scheme has better performance in resolving blocking and achieving high throughput, especially in high-density vehicle scenarios.

Manufacturing of a Magnetic Composite Flexible Filament and Optimization of a 3D Printed Wideband Electromagnetic Multilayer Absorber in X-Ku Frequency Bands.

With the multiplication of electronic devices in our daily life, there is a need for tailored wideband electromagnetic (EM) absorbers that could be conformed on any type of surface-like antennas for interference attenuation or military vehicles for stealth applications. In this study, a wideband flexible flat electromagnetic absorber compatible with additive manufacturing has been studied in the X-Ku frequency bands. A multilayer structure has been optimized using a genetic algorithm (GA), adapting the restrictions of additive manufacturing and exploiting the EM properties of loaded and non-loaded filaments, of which the elaboration is described. After optimization, a bi-material multilayer absorber with a thickness of 4.1 mm has been designed to provide a reflectivity below −12 dB between 8 and 18 GHz. Finally, the designed multilayer structure was 3D-printed and measured in an anechoic chamber, achieving −11.8 dB between 7 and 18 GHz. Thus, the development of dedicated materials has demonstrated the strong potential of additive technologies for the manufacturing of thin wideband flexible EM absorbers.

Design of a Transparent System for Mutual Coupling Reduction of Microstrip Array Antennas with Confined Water

Herein, a new method for minimizing mutual coupling of an antenna array with confined water is proposed. In multiantenna systems, mutual coupling reduction is needed to sustain array signal processing efficiency. There are currently a variety of ways to suppress coupling, including defected ground, electromagnetic (EM) bandgaps, and advanced structures. The water absorption characteristic is devised in this innovative approach to minimize mutual coupling without a permanent alteration in the structure. Surface current between two antennas is cancelled using permittivity and water depth in a new configuration. A plexi‐glass confined water is added between the propagating elements to achieve this aim. The rectangular microstrip patch of transparent conducting components serves as the antenna array. Using scattering theories, numerical EM calculations, and anechoic chamber tests, the suggested technique shows a 15 dB decrease in coupling at center frequency (7 GHz). Other propagating functions have also been improved. The suggested framework can be used in multifunction communication networks, aerial vehicle antennas, solar panels, and naval communications because of its optical transparency.

Heatable Vehicle Glazing with Antennas

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;In this paper, we propose a vehicle antenna system on a conductive heat reflecting window. A slot antenna in a heatable vehicle glazing established between the heating bus bar, bus bar extension and the peripheral edge of an electrically conductive IR reflective coating. The antenna slot may be fed directly by a voltage source, a current source, or a coupled coplanar line at a position to excite both fundamental and higher order modes for multiband antenna applications. The slot antenna can be also established between split heating bus bars or heating bus bar extension to reduces heat loss and improve antenna efficiency. Multiple antennas can be integrated into the heatable glazing for multiband applications and/or diversity antenna systems. Results from simulation on the vehicle are compared with measurements.&lt;/div&gt;&lt;/div&gt;

Reconfigurable Antenna for UAV-Assisted Wide Coverage Air-to-Ground Communications

A wide-coverage unmanned aerial vehicle (UAV) antenna system for air-to-ground communications is proposed in this paper. The proposed antenna system has reconfigurable beam patterns based on five sets of dual-polarization and high gain antennas. Each antenna set is configured by a dual-polarization crossed inverted-V radiator and switched feed network to drive switched beamforming operations. Depending on the switch modes of the proposed antenna, main beam direction and circular polarization types can be independently selected. Further, each antenna set is faced toward the ground level at different angles from the center of UAV to provide wide beam coverage. To verify the antenna performance, each antenna set is designed at the center frequency of 5.7 GHz and total five sets are integrated with a switched feed network and a microcontroller. To implement the wide angle switched beamforming with 2-D angle-shifted main beams, a 3-D printed conformal fixture is used to connect both the antenna module and a drone body. The maximum measured bandwidth was more than 22% and the measured peak gain with the de-embedded switch feed network loss was about 10.2 dBic.

Method for prediction of EMI Emissions from Automotive Ethernet to Vehicle Antennas

Abstract. In automotive application new point-to-point (P2P) wideband communication systems e.g. Automotive Ethernet 100BASE-T1 imply an increasing effort in safeguarding its electromagnetic compatibility (EMC). The state-of-the-art EMC safeguarding process proposes a pre-compliant system level test before the vehicle level test, which may have significant variation in test results due to the different electromagnetic environment. This work presents an approach to calculate the emission signal at the vehicle antenna from the ECU output signal given by the power spectral density (PSD) of the Automotive Ethernet ECUs. The determination is performed via a transfer function which describes the coupling between the Ethernet wire harness and the antenna. This approach considers the modelling of the complex vehicle environment by the transfer function which promises the determination of an accurate emission signal before performing the vehicle level test. Further, the transfer function for a specifically EMC critical cable harness routing along the cockpit area is analyzed in more detail with a 3D simulation, which validates the chosen measurement technique of the transfer function.

A Compact Four-Channel MIMO 5G Sub-6 GHz/LTE/WLAN/V2X Antenna Design for Modern Vehicles

This article presents a compact vehicle antenna design that supports four-channel MIMO operations for 5G Sub-6, LTE, Wireless Local Area Network (WLAN), and Vehicle-to-Everything (V2X) communications with a total volume of only 152 mm in diameter and 20 mm in height. The proposed antenna system consists of four dielectric-loaded wideband horns, a common top plate, an annular slot, and four shorting pins. It produces four vertically polarized diversity patterns in azimuth and a relatively uniform azimuthal coverage in the selection combining mode. The operating principles and the key design parameters of the proposed antenna are discussed in detail. The measurement VSWR, gain, patterns, and MIMO performance of a fabricated antenna prototype mounted on a 1 m circular ground plane are presented and compared with simulations with good agreements.

Comparing and Analysis of Test and Evaluation Methods for Connected Vehicle Communication Antenna System

With the development of Connected Vehicle, various of on-board applications and functions rely on stable, reliable and fast-response wireless connections furtherly, making it more urgent and widespread for vehicles to be equipped with relevant antenna systems such as positioning and communication. There are many types of vehicle antenna systems, together with a wide range of installation locations and a complex electronic environment which brings a huge challenges to the development of antenna manufacturers and the matching of automobile OEMs. In order to carry out the R&D, matching and testing of the vehicle antenna system better, various parties have proposed a multi-dimensional test and evaluation methods, but there is still a lack of horizontal evaluation between them. This paper analyses the requirements of automotive antenna system evaluation, sorts out and compares the technical paths of various common solutions, summarizes the characteristics and differences of various solutions, and provides a research foundation for further optimizing the vehicle-level antenna system test and evaluation program.

The Recent Advancement in Unmanned Aerial Vehicle Tracking Antenna: A Review.

Unmanned aerial vehicle (UAV) antenna tracking system is an electromechanical component designed to track and steer the signal beams from the ground control station (GCS) to the airborne platform for optimum signal alignment. In a tracking system, an antenna continuously tracks a moving target and records their position. A UAV tracking antenna system is susceptible to signal loss if omnidirectional antenna is deployed as the preferred design. Therefore, to achieve longer UAV distance communication, there is a need for directional high gain antenna. From design principle, directional antennas are known to focus their signal energy in a particular direction viewed from their radiation pattern which is concentrated in a particular azimuth direction. Unfortunately, a directional antenna is limited by angle, thus, it must always be directed to the target. The other limitation of a UAV mechanical beam steering system is that the system is expensive to maintain and with low reliability. To solve this problem, we are proposing the use of MIMO technology as a readily available technology for UAV beyond line of sight technology. Although UAV antenna tracking is domiciled in the mechanical beam steering arrangement, this study shows that this native technology could be usurped by MIMO beam forming.

A Miniaturized High-Gain Flexible Antenna for UAV Applications

A miniaturized high-gain flexible unmanned aerial vehicle (UAV) antenna is presented in this study. The proposed antenna basically comprised of three parts of printed patch in series, etched on dielectric substrate. And, a flexible cable is loaded on the bottom of dielectric substrate. A coplanar waveguide (CPW) with asymmetric ground feeding structure is employed to provide good impedance matching. The surface current can achieve the same phase for the straight-line patch and the flexible cable, through adjusting the dimensions of the meander line patch, which increases radiation gain while maintaining the compact size. As an important merit to be highlighted, the flexible cable can greatly reduce the volume and aerodynamic drag of the antenna. It has a low-profile compact size of 196 × 15 × 0.8 mm3 (excluding flexible cable). The results show that the omnidirectional gain fluctuates within 4.5 ± 0.1 dBi in the desired band (902 MHz–928 MHz), which is high enough for the UAV application. Details of the antenna design and experimental results are presented and discussed.

Study on System Design and Variation of Vehicle Antenna Eccentricity test

This paper takes the vehicle antenna as the research object, and carries out a comparative study on vehicle antenna testing by improving the NF-FF transformation algorithm and combining the special application scenarios of vehicle testing. Research has shown that when the vehicle is used as the DUT, there is a significant difference in the near-field test data when the vehicle antenna is in the center and the geometric center of the vehicle is in the test center; however, through correct NF-FF transformation processing, both far-field radiation patterns are consistent. It shows that the far-field radiation information of the whole vehicle can be obtained under the processing of spherical near-field measurement and near-far-field transformation. This conclusion provides a basis for the promotion of wireless performance testing of the vehicle.

Design and Simulation of vehicle antenna in different frequency band

In order to meet the needs of a variety of automotive communication services, vehicle antennas working in multiple frequency bands are emerging. It promotes the development of antenna in the direction of multifrequency and miniaturization. Based on the above research background, this paper designs a vehicle antenna for the requirements of mobile communication frequency band. The antenna consists of a half-t monopole and a half cone monopole, which are vertically placed on a metal floor. T-shaped branches mainly work at low frequency, while cone-shaped branches mainly work at high frequency. The tapered branch is used to improve the impedance matching, increase the bandwidth of the antenna, and the antenna miniaturization is realized by using half reduction technology. The antenna is processed and measured, and the working frequency bands are 720MHz-960MHz and 1.6GHz-4GHz, covering amps, GSM, LTE and 5G.

Research on microwave heating structure optimization of auxiliary material box of road maintenance vehicle

The arrangement and spacing of microwave comprehensive maintenance vehicle antenna array directly affect the heating efficiency and heating uniformity of asphalt mixture. In order to improve the heating uniformity of asphalt mixture, this paper proposes a microwave heating structure based on auxiliary materials box, and optimizes the microwave heating structure of auxiliary materials box of road maintenance vehicle through CST simulation platform. Firstly, in the way of side-by-side arrangement of the antenna array, the spacing of the antenna array is optimized, and the heating uniformity of the asphalt mixture in the auxiliary material box is the best when the spacing is 132mm×155mm under side-by-side arrangement. Then, under the optimal arrangement spacing, the orthogonal arrangement of antenna array was put forward, and it was concluded that under this arrangement, the heating uniformity of asphalt mixture increased by 12.1%, and the proportion of asphalt mixture increased by 8.7% at 80°C -160°C. This conclusion has certain reference value to the improvement of the heating effect of the auxiliary material box heating system.