Commercial Antenna Research Articles

Compact Archimedean spiral antenna with high gain for electrostatic discharge detection

AbstractA compact Archimedean spiral antenna with high gain for electrostatic discharge (ESD) detection is investigated. A frustum‐shaped cavity proposed in this work is formed to optimise the maximum antenna gain. Additionally, a helix arm is loaded to enhance antenna gain in lower band. The measured results demonstrate that the proposed antenna, which employs a unidirectional radiation mode, exhibits a maximum antenna gain ranging from −0.74 dBi to 9.46 dBi and a voltage standing wave ratio less than 3 across a frequency range of 0.65–5 GHz. A test system consisted of proposed antenna and a commercial ESD detection antenna is established. The verified results indicate that the proposed antenna has a performance close to the commercial antenna, so that proposed antenna with compact size is preferred to be utilised for ESD detection.

Directive Millimeter-Wave End-Fire Diplexing Antenna for IoT Applications

Millions of passengers use High-speed trains (HSTs) daily, in the world. The roofs of HSTs can be equipped with a variety of transmitting and receiving antennas to accommodate high-data-rate Internet services with reliable radio access for passengers. The design of commercial antenna systems is a compromise between cost, size, manufacturability, and performance. This paper proposes a new, compact and low-cost two-port millimeter-wave diplexing directive end-fire antenna, which is designed, fabricated and tested. The proposed antenna is made of a tapered slot antenna and a diplexing structure based on transitions in stacked Printed Circuit Boards (PCBs). The ports of the antenna cover the frequency band 25.9-32.4 GHz (6.5 GHz) and 34.6-37.1 GHz (2.5 GHz). In all operating frequency bands, measured isolation between input ports exceeds 24 dB. Furthermore, symmetric directive end-fire radiation patterns are obtained experimentally, with low side lobe level and low front-to-back ratio. All these features make the proposed diplexing antenna suitable for high-speed railway wireless networks.

Analysis of dielectric resonator antenna using natural fiber reinforced polymer composites

This work aims to demonstrate the viability of replacing natural fiber reinforced polymer composites for hard ceramics in millimeter-wave dielectric resonator antennas (DRA). The dielectric characteristics of three novel natural fiber reinforced polymer composites were determined using the Lichtenecker logarithmic mixing law. Using two commercial antenna design software packages, CST Studio and ANSYS HFSS, the resulting dielectric characteristics were utilized to study a probe-fed rectangular DRA. Natural fiber-reinforced polymer-based DRAs offer a wider bandwidth than ceramic-based DRAs. Close coupling is obtained by the three natural fiber-reinforced polymer-based antennas and the ceramic DRA. In all cases, the impedance bandwidths observed are the consequence of quasi-TM111 mode radiation. HFSS studies indicate that the resonance frequency of the natural fiber reinforced polymer based DRAs is roughly 75 percent higher than that of the ceramic DRA. CST results indicate that the resonance frequency of the natural fiber polymer-based DRA is approximately 88 percent higher than that of the ceramic DRA. Natural fiber reinforced Polymer-based DRAs have three times the −10 dB impedance bandwidth of ceramic-based DRAs.

Performance Analysis of the GNSS Instantaneous Ambiguity Resolution Method Using Three Collinear Antennas

Attitude determination technology based on the global navigation satellite system (GNSS) has been widely studied due to its low cost and no accumulation of errors. The essential task of attitude determination using GNSS is to estimate the pointing vector of the baseline. However, when the user is located in the complex urban canyon environment, the success rate of ambiguity will be significantly reduced, resulting in inaccurate attitude determination results. This paper presents improvements to existing methods for ambiguity resolution using collinear antennas. The collinear receiver system is built with low-cost commercial antennas to verify the method’s performance. Results indicate a success rate of over 68% with just four satellites, demonstrating significant improvement over traditional LAMBDA method. This method reduces operation time while maintaining a high success rate, with a potential reduction of up to three orders of magnitude compared to the baseline constrained LAMBDA method. The method also exhibits potential anti-multipath capability, reducing RMSE of the pointing vector coordinate component by 60.3%, 87.5%, and 94.2% in the urban canyon environment with significant multipath effects. These results demonstrate the practical effectiveness and potential of the method for ambiguity resolution in challenging environments.

A GNSS Spoofing Detection and Direction-Finding Method Based on Low-Cost Commercial Board Components

The Global Navigation Satellite System (GNSS) is vulnerable to deliberate spoofing signal attacks. Once the user wrongly locks on the spoofing signal, the wrong position, velocity, and time (PVT) information will be calculated, which will harm the user. GNSS spoofing signals are difficult to carry out spoofing attacks in the direction of arrival (DOA) of the real signal, so the spoofing detection method based on DOA is very effective. On the basis of identifying spoofing signals, accurate DOA information of the signal can be further used to locate the spoofer. At present, the existing DOA monitoring methods for spoofing signals are mainly based on dedicated antenna arrays and receivers, which are costly and difficult to upgrade and are not conducive to large-scale deployment, upgrade, and maintenance. This paper proposes a spoofing detection and direction-finding method based on a low-cost commercial GNSS board component (including an antenna). Based on the traditional principle of using a multi-antenna carrier phase to solve DOA, this paper innovatively solves the following problems: the poor direction-finding accuracy caused by the unstable phase center of low-cost commercial antennas, the low success rate of spoofing detection in a multipath environment, and the inconsistent sampling time among multiple low-cost commercial GNSS boards. Moreover, the corresponding prototype equipment for spoofing detection and direction-finding is developed. The measured results show that it can effectively detect spoofing signals in open environments. Under a certain false alarm rate, the detection success rate can reach 100%, and the typical direction-finding accuracy can reach 5°.

Microstrip Copper Nanowires Antenna Array for Connected Microwave Liquid Sensors

In this contribution, a 25 GHz planar antenna, designed and realized in microstrip technology, is exploited as a lightweight and compact liquid sensor. The high working frequency allows minimization of the sensor dimension. Moreover, particular attention was paid to keeping the design cost low. Indeed, the frequency of 25 GHz is widely exploited for many applications, e.g., up to the last decade concerning radars and, recently, 5G technology. Available commercial antennas allowed minimization of the effort that is usually required to design the microstrip sensor. The antenna was in-house realized, and the microstrip Cu conductor was modified through controlled anodic oxidation in order to enhance the sensing features. The sensor capability of detecting the presence and concentration of ethanol in water was experimentally demonstrated. In detail, a sensitivity of 0.21 kHz/(mg/L) and an average quality factor of 117 were achieved in a very compact size, i.e., 18 mm × 19 mm, and in a cost-effective way. As a matter of fact, the availability of devices able to collect data and then to send the related information wirelessly to a remote receiver represents a key feature for the next generation of connected smart sensors.

Coexistence Analysis Between IMT-2020 and AES operating in L Band on a Final Approach

This paper is regarding the statistical coexistence analysis between a cluster of International Mobile Telecommunication 2020 (IMT-2020) Base Stations and an Aircraft Earth Station (AES) operating during flight time in the L Band on a final approach. We assess the cumulative distribution function (CDF) of interference-over-noise ratio (INR) considering the fuselage attenuation contribution and compare it with the AES protection criteria. Our coexistence analysis approach considers the use of a high gain AES commercial antenna model, for an aircraft at two different altitudes, 187 m and 83 m, for 3600 m and 1600 m of horizontal distance from the runway threshold, respectively. Therefore, considering the IMT-2020 suburban scenario near the airport, simulation results presented an INR that met the protection criteria for 100% and 99.95% of the time for the distances of 3600 m and 1600 m from the runway, respectively, making the spectrum sharing feasible between systems. To the best of our knowledge, this is the first time in the literature that fuselage attenuation considering part of the plane, in the L-band is presented in a statistical coexistence analysis.

Inspection and Imaging of Tree Trunk Defects Using GPR Multifrequency Full-Waveform Dual-Parameter Inversion

Ground-penetrating radar (GPR) has been regarded as a potentially efficient way of evaluating the growth status of trees and preventing deterioration associated with trunk defects. However, the majority of current GPR data inversions focused on imaging the macroscale location of defects. As the first attempt to seek a preferable quantitative inversion methodology for specifying tree protection and remedies, this paper proposes a full-waveform inversion approach involving dual-parameter attributes applied to common-offset GPR data from a commercial antenna. Specifically, the synchronous inversion of both dielectric constant and conductivity improves the identification accuracy of certain defect types. In particular, both a multi-frequency strategy and total-variation regularization are seamlessly introduced to assure inversion stability by overcoming local minima and cycle skipping. Through an irregular trunk model test, the effectiveness of the optimized inversion is initially verified by presenting the precise features of the crack, hollow, and decay with the dual parameter inversion results. In addition, several other synthetic trunk models and in-site trunk model tests further demonstrate the robustness and practicability of the proposed algorithm, which can offer more specific and comprehensive guidance for the formulation of tree protection and restoration measures.

Horn Antenna Analysis and Simulation for the 18-40 GHz Frequency Band

An antenna is a type of transducer that converts radio signals into alternating electromagnetic waves before transmitting them into space. Polarization is a phase in the selection and installation of an antenna. It can send and receive signals. An antenna is a metal structure that transmits or receives electromagnetic radiation. The antenna, on the other hand, connects the directing device to free space. It sends a signal from the generator into space through transmission cables. High-frequency double-ridged horn (DRH) antennas for electromagnetic compatibility (EMC) are built using a special technique. When using this technique, at the beginning, consider a standard DRH antenna that operates between 1 and 18 GHz. A detailed sensitivity analysis of the 1-18 GHz DRH antenna's structural characteristics addresses some of the DRH antenna's weaknesses, notably in terms of its radiation pattern at higher frequencies. After that, the design is frequency scaled up to support a greater frequency range. This technology might be used to build a wideband DRH antenna that can operate between 18 and 40 GHz. Because the new antenna has a lower frequency ratio of 1:12.2 compared to the normal antenna's 1:18 ratio, we may choose the appropriate frequency window for scaling up. A voltage standing wave ratio (VSWR) of less than a single main lobe that is uninterruptedly oriented along the horn axis and a minimum of 10 dB of acceptable broadband gain are all necessary. The resulting design was used to produce a prototype antenna that was smaller than previous commercial antennas. The dimensions and design objectives were used to develop the prototype.

Efficient Computation of Electromagnetic Coupling From Various Types of Antennas Based on Reciprocity Theorem

In the design of complex electronic systems, such as electric vehicles, electromagnetic coupling between a specific component and an antenna should be quantitatively estimated according to the radiated emission (RE) and radiated immunity (RI) standards. However, full-wave electromagnetic simulations of complex systems and antennas in a large space take much time and effort. The decomposition method based on reciprocity and Huygens's principle, which enables the separate analysis of source and victim parts, has been previously proposed for efficient analysis of coupling to a lumped port of the victim antenna. In this article, the decomposition method along with the extraction of an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameter block is extended to handle the dominant transverse electric mode in a waveguide antenna. The proposed method removes the difficulty and uncertainty in the modeling process of a commercial waveguide antenna. Also, while applying the decomposition method, Huygens's principle is additionally applied to further reduce the full-wave simulation time of a large empty space. The proposed methods are validated with full-wave electromagnetic simulations, and also experimentally applied to RI estimation. The proposed time-efficient techniques can realize the full-wave computation of RE and RI for real complicated systems and commercial antennas.

WheelLoc: Practical and Accurate Localization for Wheeled Mobile Targets via Integrated Sensing and Communication

Practical and accurate localization systems are important to mobile targets that enable promising services such as navigation and augmented reality. With the proliferation of WiFi, existing WiFi-based localization systems have leveraged RSSI, fingerprints, landmarks, time of arrival, or angle of arrival to locate targets, while no related work pays attention to mobile targets themselves. For wheel-driven mobile targets, such as vehicles, bikes, and wheeled robots, we design and implement WheelLoc, a novel WiFi-based localization system leveraging the rotation of wheels. The specially designed WheelLoc hardware is cost-effective and self-powered with the composition of three commercial antennas and a solar cell, which is also easy to be installed on wheels. A hybrid WheelLoc algorithm is further proposed to realize accurate localization in diverse environments, whether the wheel of targets is static or mobile, indoor or outdoor, on flat or bumpy ground. The movements of individual antennas are exploited to emulate linear, cycloid, and circular antenna arrays using a new formulation of Synthetic Aperture Radar (SAR). Extensive experiments are conducted on bikes in the real world. Performance results demonstrate that WheelLoc does not require any user interaction, yet achieves comparable accuracy with the state-of-the-art localization systems using WiFi.

Designing and Implementing a Microstrip Antenna on LoRa Frequency for Smart Meter Communication

The long-range wide area network (LoRaWAN) has been widely used for sensor networks, including smart meter (SM). The SM can report power consumption to the control center automatically via a communication link. An antenna is a key component to indicate an effective communication system. The microstrip antenna (MSA) works based on the unidirectional radiation pattern. The advantages of MSA are its light weight, small size, and ability to be easily etched on a print circuit board. These advantages are needed for the SM communication because SMs are installed on electric poles that have limited space. In this pa- per, we implement the MSA for SM communication on LoRaWAN technology that operates at a frequency of 920–925 MHz in Thailand. The proposed MSA is used to design a new path loss model for LoRaWAN in urban areas. Results show that our MSA is effectively close to commercial antennas in a 2.2 km range, with the packet delivery ratio reaching 52.93%. We analyze the results by using a mathematical equation that includes the free space model, the Okumura–Hata model, root mean squared error, and coefficient of determination.

A Wide-Angle Pattern Diversity Antenna System for mmWave 5G Mobile Terminals

A shared ground shared radiator with wide angular coverage for mmWave 5G smartphones is proposed in this paper. A four-element corporate-fed array with conventional impedance matched power divider is designed. Stepped impedance transformers are integrated with the corner most elements to achieve pattern diversity with wide angular coverage without significant compromise in gain. The proposed three-port shared radiator conformal commercial antenna could be easily integrated with commercial mmWave 5G smartphones. All the three ports’ excitations operate in the 28 GHz band. Radiation pattern bandwidth of the multi-port system is high. The gain variation is from 6 to 11 dBi amongst the ports and across the operating spectrum. The highest mutual coupling is 10 dB, in spite of the electrically connected structure. The proposed shared radiator element has a wide angular coverage of 100°, maintaining high front-to-back ratio when the respective port is excited. Simulation and measurement results for the proposed structure are illustrated in detail.

On the effect of S-parameter stability of antenna and coupler on electrical balance duplexing

Electrical Balance Duplexers (EBDs) provide transmit-receive isolation to implement a form of self-interference cancellation to facilitate simultaneous transmission and reception from a single antenna in systems like In-Band Full-duplex (IBFD) transceivers. EBD works by coupling transmitter, receiver, antenna, and balancing impedance using a hybrid coupler. In recent pieces of literature, antenna impedance variations are considered the main factor limiting the EBD isolation bandwidth, while the EBD balancing impedance needs to be equal as much as possible to the antenna impedance to achieve high isolation. But hybrid couplers are also not ideal elements, and their S-parameters are not stable in the frequency domain. In this work, five broadband RF devices (two antennas, two couplers, and a 50-Ohm RF-load) are used to form four EBD set-ups. One of the antennas, designed by the authors, has more impedance stability in the frequency domain than the other one, which is a commercial antenna. Also, one of the couplers, designed by the authors, has more S-parameter stability in Ultra-Wideband (UWB) frequency domain than the other one, which is a commercial UWB coupler. The implemented EBDs show that when both antenna and coupler have strong S-parameter stabilities in the frequency domain, wider isolation bandwidth (UWB 1.5–3.5 GHz range) and higher EBD isolation are obtained.

Point Positioning Capability of Compact, Low-Cost GNSS Modules: A Case Study

Global Navigation Satellite System (GNSS) provides precise Position, Velocity, and Timing (PVT) information. Various types of receivers of varying cost and complexity are used for collection and use of GNSS data. Currently, cost-effective, compact, low power consuming, multi-constellation enabled, single, or dual-frequency GNSS modules are being increasingly available having the capability of providing modest position solution accuracy. This paper presents the results of GPS, BeiDou, and GPS + BeiDou hybrid positioning capabilities of few commercially available modules based on systematic analysis from data collected during two time periods from two locations of India using geodetic and commercial patch antennas w.r.t. the reference points created through PPP (Precise Point Positioning). The results are compared with those provided a survey-grade GNSS receiver. It is witnessed that, selected single frequency module can provide 3-4m 2DRMS (Distance Root Means Square) precision and their dual frequency counterparts can provide 2DRMS solution precision around 3 m in GPS-only operation, around 7 m in BeiDou-only operation and around 3.5 m in case of GPS + BeiDou hybrid operation. The performance of the compact modules clearly presents the cost-performance benefit of the compact modules for real-time applications and the results of this study would help in understanding the capabilities of these modules for mass-market applications.

The Use of 3D Printing Technology for Manufacturing Metal Antennas in the 5G/IoT Context.

With the rise of 5G, Internet of Things (IoT), and networks operating in the mmWave frequencies, a huge growth of connected sensors will be a reality, and high gain antennas will be desired to compensate for the propagation issues, and with low cost, characteristics inherent to metallic radiating structures. 3D printing technology is a possible solution in this way, as it can print an object with high precision at a reduced cost. This paper presents different methods to fabricate typical metal antennas using 3D printing technology. These techniques were applied as an example to pyramidal horn antennas designed for a central frequency of 28 GHz. Two techniques were used to metallize a structure that was printed with polylactic acid (PLA), one with copper tape and other with a conductive spray-paint. A third method consists of printing an antenna completely using a conductive filament. All prototypes combine good results with low production cost. The antenna printed with the conductive filament achieved a better gain than the other structures and showed a larger bandwidth. The analysis recognizes the vast potential of these 3D-printed structures for IoT applications, as an alternative to producing conventional commercial antennas.

Compact, Low-cost GNSS Modules for Precise Point Positioning

Global Navigation Satellite System (GNSS) uses Precise Point Positioning (PPP) technique to find out accurate geolocation information of any point. Generally, costly, geodetic GNSS receivers are used for PPP. This manuscript presents the results of studies on the usability of commercial, compact, cost-effective GNSS modules with commercial antennas for PPP in comparison to commonly used geodetic, costly receivers from India, which is a excellent location for GNSS use. Compact GNSS modules from two manufacturers are used in the study, and the encouraging results show the clear advantage of cost, size, and power requirements of such modules. The modules provide sub-cm horizontal solution accuracy which is very similar to those obtained using geodetic receivers, and around 20 cm accuracy in the vertical coordinate, which is slightly inferior to the results provided by the geodetic reveivers. Results of this novel study would be useful for implementing cost-efficient GNSS PPP in real life, in highly demanding geodetic applications including CORS establishment and PPP.

Design and Simulation of Millimeter-Wave Broadband Modified Ankh-Key Antenna for 5G and Beyond Technologies Applications

In this paper, a modified Pharaonic Ankh-Key antenna is proposed to support modern technologies and enhance the usage of 5G and next generations applications providing better performance compared to the previously designed Ankh-Key antenna [3]. The multiband antenna can operate in 28GHz band, 37 GHz band, and all bands from 49 GHz to beyond 140 GHz with peak gain between 6.9 dBi to 10.2 dBi along the operating spectrum. The single layer antenna is simply designed with dimensions 12.75 mm x 18.7 mm x 0.787 mm using Rogers/Duroid RT 5880 of ε r = 2.2 and tanδ = 0.0009 promising a lower cost and easy-to-fabricate antenna compared to the existing commercial antennas. The antenna is simulated using Ansys HFSS and CST suite simulators and the results where compared to the previously designed Ankh-Key antenna achieving much better performance and wider bandwidths.

Flat Yarn Fabric Substrates for Screen‐Printed Conductive Textiles

Herein, flat yarn‐based polyethylene terephthalate (PET) fabrics as substrates for screen printing conductive inks are described. The effect of the screen‐printing parameters, such as the screen mesh size (70 or 120 pixels in.−1) and the number of printing cycles, is investigated. The uniformity of the screen‐printed layers and their electrical properties are directly related to the yarn shape, substrate roughness, and printing conditions. Minimum average sheet resistance of 16 ± 3 mΩ sq−1 is achieved on the flat yarn PET fabrics, and there is little change in the electrical performance after 1000 bending cycles. To demonstrate the impact of yarn shape on an E‐textile application, wearable antennas are fabricated using the screen‐printed PET fabrics. The antennas are designed to operate at 2.4 GHz, which is a widely used unlicensed frequency for public wireless local area network services, Bluetooth, and radio frequency identification (RFID) services. The effects of the uniformity and conductivity of the printed layers on the antenna performance are analyzed. In open‐area field tests, the textile antennas show better performance than commercial antennas. The results of this study will help improve the understanding of how the ink/substrate interface affects the screen‐printing process and to advance the manufacturing technology for conductive patterns.

3D scanner technology implementation to numerical modeling of GPR

This study presents an integration of 3D scanned objects into numerical modeling for ground-penetrating radar (GPR). The characteristics of antenna, features of surrounding medium and the realistic design of a buried object are decisive for the success of the numerical modeling. Realistic antenna design has become one of the remarkable developments of the numerical modeling by Finite-Difference Time Domain (FDTD) method. The antenna models with the specific features of commercial GPR antennas, allow researchers to obtain much closer synthetic response to measurements. In addition, lossy and inhomogeneous soil mixtures with different water content can be included in numerical models. Despite the realistic description of GPR antennas and soil types, buried objects are still roughly defined using basic geometric shapes. This article presents an alternative approach using outputs of the 3D scanner as an input into gprMax software to overcome more complex and realistic shapes of the buried objects. For this purpose, a bone fragment belonging to a bovine was firstly simulated with a basic geometric object (cylinder) and then modeled with the realistic shape of the bone, which was obtained from 3D scanner. In this way, the numerical modeling can be performed with the real shape of the object in the lossy, inhomogeneous surrounding medium by using a realistic modeled commercial antenna.