Electronics

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18 pages, 10824 KiB

Open AccessArticle

Pattern-Reconfigurable, Vertically Polarized, Wideband Electrically Small Huygens Source Antenna

by Yunlu Duan, Ming-Chun Tang, Mei Li, Zhehao Zhang, Qingli Lin and Richard W. Ziolkowski

Electronics 2025, 14(3), 634; https://doi.org/10.3390/electronics14030634 - 6 Feb 2025

Viewed by 596

A pattern-reconfigurable, vertically polarized (VP), electrically small (ES), Huygens source antenna (HSA) is demonstrated. A custom-designed reconfigurable inverted-F structure is embedded in a hollowed-out cylindrical dielectric resonator (DR). It radiates VP electric dipole fields that excite the DR’s HEM_11δ mode, which in [...] Read more.

A pattern-reconfigurable, vertically polarized (VP), electrically small (ES), Huygens source antenna (HSA) is demonstrated. A custom-designed reconfigurable inverted-F structure is embedded in a hollowed-out cylindrical dielectric resonator (DR). It radiates VP electric dipole fields that excite the DR’s HEM_11δ mode, which in turn acts as an orthogonal magnetic dipole radiator. The HSA’s unidirectional properties are thus formed. It becomes low-profile and electrically small through a significant lowering of its operational frequency band by loading the DR’s top surface with a metallic disk. The entire 360° azimuth range is covered by each of the HSA’s four 90° reconfigurable states, emitting a unidirectional wide beam. A prototype was fabricated and tested. The measured results, which are in good agreement with their simulated values, demonstrate that the developed wideband Huygens source antenna, with its 0.085 λ_L low profile and its 0.20 λ_L × 0.20 λ_L compact transverse dimensions, hence, electrically small size with ka = 0.89, exhibits a wide 14.1% fractional impedance bandwidth and a 6.1 dBi peak realized gain in all four of its pattern-reconfigurable states. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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19 pages, 15140 KiB

Open AccessArticle

Evaluation of Impact of Soil on Performance of Monopole Antenna for IoT Applications in Urban Agriculture

by Nikolay Todorov Atanasov, Blagovest Nikolaev Atanasov and Gabriela Lachezarova Atanasova

Electronics 2025, 14(3), 544; https://doi.org/10.3390/electronics14030544 - 29 Jan 2025

Viewed by 676

Abstract

Built indoor IoT-based urban farms successfully combine the cultivation of fresh vegetables with attractive architectural designs. Moreover, implementing IoT-driven urban agriculture requires installing multiple IoT devices containing sensors, controllers, transceivers, and antennas for real-time data transmission. In this context, several factors, including the [...] Read more.

Built indoor IoT-based urban farms successfully combine the cultivation of fresh vegetables with attractive architectural designs. Moreover, implementing IoT-driven urban agriculture requires installing multiple IoT devices containing sensors, controllers, transceivers, and antennas for real-time data transmission. In this context, several factors, including the height of the IoT device above the soil level and the water content in the soil, can affect antenna performance and, consequently, the propagation of radio waves. This paper presents the results from numerical and experimental studies that evaluate the impact of soil on the performance of a monopole antenna for three different antenna positions relative to the soil in a pot and two soil water contents, presented by twelve scenarios. The results show that the antenna has a stable performance in six of the twelve scenarios, with a minimal shift in the resonant frequency of 3% and a narrowing of the frequency bandwidth by 2% compared to the antenna in free space. In the worst-case scenario, the antennas demonstrate a reduction in radiation efficiency of 44%, with the frequency bandwidth narrowing by up to 14% for the antenna fabricated on a PLA substrate and up to 17% for the one built on a foam board substrate. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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17 pages, 8726 KiB

Open AccessArticle

A Full Calibration Approach on a Drone-Borne Platform for HF Antenna Measurements in Smart Grid Energy Facilities

by Marius Pastorcici, Andreea Constantin, Adelaida Heiman and Razvan D. Tamas

Electronics 2024, 13(15), 3039; https://doi.org/10.3390/electronics13153039 - 1 Aug 2024

Viewed by 970

Abstract

Emerging data processing techniques brought back into attention the HF range communication as an interesting alternative to third-party solutions for IoT applications, such as data transmission in distributed energy production facilities. The physical size of HF antennas, often comparable to the surrounding objects, [...] Read more.

Emerging data processing techniques brought back into attention the HF range communication as an interesting alternative to third-party solutions for IoT applications, such as data transmission in distributed energy production facilities. The physical size of HF antennas, often comparable to the surrounding objects, require in situ radiation measurements resulting in site-customized antenna design and positioning, and consequently in a higher reliability of such HF grid communications. Drone-borne measuring systems are already known as a flexible solution, but are mostly restricted to higher frequency ranges where full-wave, wide-band probes are feasible. In this work, we propose to use an electrically small, folded dipole as a probe for drone-borne measurements on HF antennas. We also propose a calibration approach for the effects related to the near-field zone, and to the drone body proximity; corrections on these two effects are the key methodological steps. We show that despite a realized gain figure in the order of −20 dBi, such a probe can provide stable results for near-field measurements, even at input power levels as low as 1 mW. Compared to other similar approaches, our configuration provides a wider frequency band of operation, higher stability in terms of pattern diagram, and a lower cost. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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15 pages, 7223 KiB

Open AccessArticle

Flexible Wearable Antenna for IoT-Based Plant Health Monitoring

by Nikolay Todorov Atanasov, Blagovest Nikolaev Atanasov and Gabriela Lachezarova Atanasova

Electronics 2024, 13(15), 2956; https://doi.org/10.3390/electronics13152956 - 26 Jul 2024

Cited by 5 | Viewed by 1701

Abstract

In recent years, the rapid development of wireless technologies has led to the widespread adoption of the Internet of Things (IoT) in various fields. One of the fastest-growing segments of IoT is the “smart” wearables sector. In the next few years, the development [...] Read more.

In recent years, the rapid development of wireless technologies has led to the widespread adoption of the Internet of Things (IoT) in various fields. One of the fastest-growing segments of IoT is the “smart” wearables sector. In the next few years, the development of flexible plant-wearable devices that can provide vital information about the physiological characteristics of plants will be essential to support the faster growth of precision agriculture. We propose a small (overall size Ø35 mm × 0.8 mm), ultra-lightweight (0.4 g), and elegant-shaped antenna for unobtrusive integration on a plant surface for application in IoT-based precision agriculture at ISM 2.45 GHz band. The radiating element has a design that resembles a dragonfly, making the antenna visually unnoticeable. We used ZZ Plant leaves as the substrate for the antenna and transparent polymer foil for encapsulating the conductive parts, achieving a highly flexible, waterproof, and chemically resistant antenna for application in harsh environments. The obtained results indicate that the antenna is resilient to changes in substrate relative permittivity up to ±20%. It exhibits high radiation efficiency (between 26% and 40%) and omnidirectional patterns across the ISM 2.45 GHz band. Moreover, the measured results align reasonably well with the simulated ones. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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17 pages, 9754 KiB

Open AccessArticle

Determination of Parameters of Radio Frequency Identification Transponder Antennas Dedicated to IoTT Systems Located on Non-Planar Objects

by Magdalena Nizioł, Piotr Jankowski-Mihułowicz and Mariusz Węglarski

Electronics 2024, 13(14), 2800; https://doi.org/10.3390/electronics13142800 - 16 Jul 2024

Cited by 2 | Viewed by 1002

Abstract

Integration of Radio Frequency Identification (RFID) technology with conductive textiles has greatly expanded the possibilities for creating smart devices that fit perfectly into the concept of the Internet of Things. The use of e-textiles for antenna manufacturing has enabled the development of a [...] Read more.

Integration of Radio Frequency Identification (RFID) technology with conductive textiles has greatly expanded the possibilities for creating smart devices that fit perfectly into the concept of the Internet of Things. The use of e-textiles for antenna manufacturing has enabled the development of a textronic RFID tag. Integration of such tags into products with often non-flat surfaces may result in exposure to changes in antenna geometry caused by bending. As a result, the antenna parameters may change, resulting in disruption of the entire tag operation. The authors, through simulation and experimental studies, analyzed the effects of bending the antennas of RFID tags operating in the HF (High Frequency) band. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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26 pages, 6189 KiB

Open AccessArticle

Unveiling New IoT Antenna Developments: Planar Multibeam Metasurface Half-Maxwell Fish-Eye Lens with Wavelength Etching

by Javad Pourahmadazar, Bal S. Virdee and Tayeb A. Denidni

Electronics 2024, 13(11), 2035; https://doi.org/10.3390/electronics13112035 - 23 May 2024

Viewed by 1436

Abstract

This study introduces a groundbreaking antenna system, the directive Metasurface Half-Maxwell Fish-Eye (MHMF) lens antenna, tailored specifically for Internet-of-Things (IoT) networks. Designed to operate at 60 GHz, this antenna ingeniously integrates a dipole antenna within a parallel-plate waveguide to illuminate a Half-Maxwell Fish-Eye [...] Read more.

This study introduces a groundbreaking antenna system, the directive Metasurface Half-Maxwell Fish-Eye (MHMF) lens antenna, tailored specifically for Internet-of-Things (IoT) networks. Designed to operate at 60 GHz, this antenna ingeniously integrates a dipole antenna within a parallel-plate waveguide to illuminate a Half-Maxwell Fish-Eye (HMFE) lens. The HMFE lens serves as a focal point, enabling a crucial high gain for IoT operations. The integration of metasurface structures facilitates the attainment of the gradient refractive index essential for the lens surface. By employing commercial Ansys HFSS software, extensive numerical simulations were conducted to meticulously refine the design, focusing particularly on optimizing the dimensions of unit cells, notably the modified H-shaped cells within the parallel waveguides housing the beam launchers. A functional prototype of the antenna was constructed using a standard PCB manufacturing process. Rigorous testing in an anechoic chamber confirmed the functionality of these manufactured devices, with the experimental results closely aligning with the simulated findings. Far-field measurements have further confirmed the effectiveness of the antenna, establishing it as a high-gain antenna solution suitable for IoT applications. Specifically, it operates effectively within the 60 GHz range of the electromagnetic spectrum, which is crucial for ensuring reliable communication in IoT devices. The directive HMFE lens antenna represents a significant advancement in enhancing IoT connectivity and capabilities. Leveraging innovative design concepts and metasurface technology, it heralds a new era of adaptable and efficient IoT systems. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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22 pages, 5575 KiB

Open AccessEditor’s ChoiceArticle

Advancing into Millimeter Wavelengths for IoT: Multibeam Modified Planar Luneburg Lens Antenna with Porous Plastic Material

by Javad Pourahmadazar, Bal S. Virdee and Tayeb A. Denidni

Electronics 2024, 13(9), 1605; https://doi.org/10.3390/electronics13091605 - 23 Apr 2024

Cited by 1 | Viewed by 1608

Abstract

This paper introduces an innovative antenna design utilizing a cylindrical dielectric Luneburg lens tailored for 60 GHz Internet of Things (IoT) applications. To optimize V-band communications, the permittivity of the dielectric medium is strategically adjusted by precisely manipulating the physical porosity. In IoT [...] Read more.

This paper introduces an innovative antenna design utilizing a cylindrical dielectric Luneburg lens tailored for 60 GHz Internet of Things (IoT) applications. To optimize V-band communications, the permittivity of the dielectric medium is strategically adjusted by precisely manipulating the physical porosity. In IoT scenarios, employing a microstrip dipole antenna with an emission pattern resembling cos¹⁰ enhances beam illumination within the waveguide, thereby improving communication and sensing capabilities. The refractive index gradient of the Luneburg lens is modified by manipulating the material’s porosity using air holes, prioritizing signal accuracy and reliability. Fabricated with polyimide using 3D printing, the proposed antenna features a slim profile ideal for IoT applications with space constraints, such as smart homes and unmanned aerial vehicles. Its innovative design is underscored by selective laser sintering (SLS), offering scalable and cost-effective production. Measured results demonstrate the antenna’s exceptional performance, surpassing IoT deployment standards. This pioneering approach to designing multibeam Luneburg lens antennas, leveraging 3D printing’s porosity control for millimeter-wave applications, represents a significant advancement in antenna technology with scanning ability between −67 and 67 degrees. It paves the way for enhanced IoT infrastructure characterized by advanced sensing capabilities and improved connectivity. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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12 pages, 7785 KiB

Open AccessArticle

A Compact 2.4 GHz L-Shaped Microstrip Patch Antenna for ISM-Band Internet of Things (IoT) Applications

by Muhammad Fitra Zambak, Samir Salem Al-Bawri, Muzammil Jusoh, Ali Hanafiah Rambe, Hamsakutty Vettikalladi, Ali M. Albishi and Mohamed Himdi

Electronics 2023, 12(9), 2149; https://doi.org/10.3390/electronics12092149 - 8 May 2023

Cited by 14 | Viewed by 5568

Abstract

Wireless communication technology integration is necessary for Internet of Things (IoT)-based applications to make their data easily accessible. This study proposes a new, portable L-shaped microstrip patch antenna with enhanced gain for IoT 2.4 GHz Industrial, Scientific, and Medical (ISM) applications. The overall [...] Read more.

Wireless communication technology integration is necessary for Internet of Things (IoT)-based applications to make their data easily accessible. This study proposes a new, portable L-shaped microstrip patch antenna with enhanced gain for IoT 2.4 GHz Industrial, Scientific, and Medical (ISM) applications. The overall dimensions of the antenna are 28 mm × 21 mm × 1.6 mm

(0.22 λ_{o}

×

0.17 λ_{o}

×

0.013 λ_{o}

, with respect to the lowest frequency). The antenna design is simply comprised of an L-shape strip line, with a full ground applied in the back side and integrated with a tiny rectangular slot. According to investigations, the developed antenna is more efficient and has a greater gain than conventional antennas. The flexibility of the antenna’s matching impedance and performance are investigated through several parametric simulations. Results indicate that the gain and efficiency can be enhanced through modifying the rectangular back slot in conjunction with fine-tuning the front L-shaped patch. The finalized antenna operates at 2.4 GHz with a 98% radiation efficiency and peak gains of 2.09 dBi (measured) and 1.95 dBi (simulated). The performance of the simulation and measurement are found to be in good agreement. Based on the performance that was achieved, the developed L-shaped antenna can be used in a variety of 2.4 GHz ISM bands and IoT application environments, especially for indoor localization estimation scenarios, such as smart offices and houses, and fourth-generation (4G) wireless communications applications due to its small size and high fractional bandwidth. Full article

(This article belongs to the Special Issue Antennas for IoT Devices)

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