Research

13 pages, 7743 KiB

Open AccessCommunication

Quad-Band Circular Polarized Antenna for GNSS, 5G and WIFI-6E Applications

by Xiaoming Liu, Haiyang Wang, Xiaofan Yang and Jinhong Wang

Electronics 2022, 11(7), 1133; https://doi.org/10.3390/electronics11071133 - 02 Apr 2022

Cited by 11 | Viewed by 3088

A quad-band circularly-polarized antenna, for applications of a global navigation satellite system (GNSS), 5G, and WIFI-6E, is designed, fabricated, and measured. The proposed antenna is formed by an L-shaped radiator, a rectangular frame ground with an L-shaped stub, and a rectangular strip at [...] Read more.

A quad-band circularly-polarized antenna, for applications of a global navigation satellite system (GNSS), 5G, and WIFI-6E, is designed, fabricated, and measured. The proposed antenna is formed by an L-shaped radiator, a rectangular frame ground with an L-shaped stub, and a rectangular strip at the opposite corner. The microstrip antenna can generate four frequency bands, covering WIFI-6E (5925–7125 MHz), 5G n77 (3300–4200 MHz), n78 (3300–3800 MHz), and the GNSS bands. This antenna generates right hand circular polarization (RHCP) waves in the low frequency band (0.95–2.11 GHz), covering GPS, BDS, GLONASS, and GALILEO applications. Moreover, an L-shaped aperture and three rectangular slits are cut on the ground to broaden the axial-ratio bandwidth at the upper band. A prototype is fabricated and measured to verify the performance of this design. It is shown that the agreement between the simulation and measurement is satisfactorily good. The measured −10 dB bandwidths for each band are 75.8% (0.95–2.11 GHz), 55.8% (3.05–5.39 GHz), 39.9% (5.84–8.19 GHz) and 10.3% (9.14–10.68 GHz), respectively. While the measured 3 dB axial-ratio bandwidths are 59.4% (1.16–2.14 GHz), 35.8% (3.23–4.64 GHz), 8.4% (5.70–6.20 GHz), and 2.6% (7.51–7.71 GHz), the measured gains are 4.56, 2.28, 4.26, and 4.30 dBi at 1.5 GHz, 3.8 GHz, 6 GHz, and 7.6 GHz, respectively. Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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24 pages, 4236 KiB

Open AccessFeature PaperArticle

Radiation Pattern Synthesis of the Coupled almost Periodic Antenna Arrays Using an Artificial Neural Network Model

by Hamdi Bilel and Aguili Taoufik

Electronics 2022, 11(5), 703; https://doi.org/10.3390/electronics11050703 - 24 Feb 2022

Cited by 4 | Viewed by 2584

Abstract

This paper proposes radiation pattern synthesis of almost periodic antenna arrays including mutual coupling effects (extracted by Floquet analysis according to our previous work), which in principal has high directivity and a large bandwidth. For modeling the given structures, the moment method combined [...] Read more.

This paper proposes radiation pattern synthesis of almost periodic antenna arrays including mutual coupling effects (extracted by Floquet analysis according to our previous work), which in principal has high directivity and a large bandwidth. For modeling the given structures, the moment method combined with the generalized equivalent circuit (MoM-GEC) is proposed. The artificial neural network (ANN), as a powerful computational model, has been successfully applied to antenna array pattern synthesis. Our results showed that multilayer feedforward neural networks are rugged and can successfully and efficiently resolve various distinctive, complex almost periodic antenna patterns (with different source amplitudes) (in particular, both periodic and randomly aperiodic structures are taken into account). An ANN is capable of quickly producing the synthesis results using generalization with the early stopping (ES) method. Significant advantages in speed and memory consumption are achieved by using this method to improve the generalization (called early stopping). To justify this work, several examples are shown and discussed. Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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17 pages, 4611 KiB

Open AccessArticle

Air and Metal Vias Combined Metamaterial-Based Lens for Radiation Performance Enhancement of Short-Pulse Tapered Slot Antenna

by Yifan Yin, Qiuyi Zhang and Shunli Li

Electronics 2021, 10(22), 2845; https://doi.org/10.3390/electronics10222845 - 19 Nov 2021

Cited by 1 | Viewed by 1695

Abstract

A post-wall-structured tapered slot antenna (PWTSA) loaded with an embedded metamaterial-based lens (metalens) is proposed and investigated for short-pulse applications. The proposed embedded metalens consists of not only a metallic delay lens, but also an airy acceleration region surrounding the lens, which is [...] Read more.

A post-wall-structured tapered slot antenna (PWTSA) loaded with an embedded metamaterial-based lens (metalens) is proposed and investigated for short-pulse applications. The proposed embedded metalens consists of not only a metallic delay lens, but also an airy acceleration region surrounding the lens, which is different from the conventional metalenses used in various tapered slot antennas and can exhibit a small equivalent permittivity. Therefore, the embedded metalens has a large usable range of permittivity and does not increase the size of the original prototype PWTSA. The post-wall structure and metalens of the proposed antenna can help it achieve a comprehensive and balanced performance, including a high fidelity, low cross-polarization, stable main-lobe direction and gain enhancement. The simulated and measured results show that without any increase in antenna size, the proposed antenna enhances the realized gain by 6.4 dB over the frequency range from 9 to 26 GHz and achieves a stable radiation with the offset of the main-lobe direction being confined to 2° up to 24.9 GHz. Furthermore, the cross-polarization levels are less than −20 dB and the fidelity is kept high for the short-pulse radiation with the frequency spectrum up to 30 GHz. Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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24 pages, 48317 KiB

Open AccessArticle

Design Optimization of Wearable Multiband Antenna Using Evolutionary Algorithm Tuned with Dipole Benchmark Problem

by Łukasz Januszkiewicz, Paolo Di Barba and Jarosław Kawecki

Electronics 2021, 10(18), 2249; https://doi.org/10.3390/electronics10182249 - 13 Sep 2021

Cited by 2 | Viewed by 2440

Abstract

In this paper we present the optimal design of wearable four band antenna that is suitable to work in the fifth-generation wireless systems as well as in cellular systems and in unlicensed bands. The design of the antenna relies on a careful study [...] Read more.

In this paper we present the optimal design of wearable four band antenna that is suitable to work in the fifth-generation wireless systems as well as in cellular systems and in unlicensed bands. The design of the antenna relies on a careful study of optimization algorithms that are suitable for antenna design. We have proposed a benchmark problem to compare different optimization algorithms. It is the space of voltage standing wave ratio and the gain of dipole antenna that was identified for wide range of dipole length and radius. Using this pre-calculated data, we have tuned the parameters of optimization routine for optimal performance with our benchmark. After this, we optimized the geometry of four-band wearable antenna. In the optimization process, we used finite-difference time-domain method together with simplified model of human body. The antenna design was assessed with a fabricated prototype. Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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20 pages, 46722 KiB

Open AccessEditor’s ChoiceArticle

Design and Optimization of Compact Printed Log-Periodic Dipole Array Antennas with Extended Low-Frequency Response

by Keyur K. Mistry, Pavlos I. Lazaridis, Zaharias D. Zaharis and Tian Hong Loh

Electronics 2021, 10(17), 2044; https://doi.org/10.3390/electronics10172044 - 24 Aug 2021

Cited by 12 | Viewed by 9617

Abstract

This paper initially presents an overview of different miniaturization techniques used for size reduction of printed log-periodic dipole array (PLPDA) antennas, and then continues by presenting a design of a conventional PLPDA design that operates from 0.7–8 GHz and achieves a realized gain [...] Read more.

This paper initially presents an overview of different miniaturization techniques used for size reduction of printed log-periodic dipole array (PLPDA) antennas, and then continues by presenting a design of a conventional PLPDA design that operates from 0.7–8 GHz and achieves a realized gain of around 5.5 dBi in most of its bandwidth. This antenna design is then used as a baseline model to implement a novel technique to extend the low-frequency response. This is completed by replacing the longest straight dipole with a triangular-shaped dipole and by optimizing the four longest dipoles of the antenna using the Trust Region Framework algorithm in CST. The improved antenna with extended low-frequency response operates from 0.4 GHz to 8 GHz with a slightly reduced gain at the lower frequencies. Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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17 pages, 6774 KiB

Open AccessArticle

Monopulse Antenna Based on Singular Spoof Surface Plasmon Polariton Structure for Angle Measurement

by Shunli Li, Qiuyi Zhang, Jinlun Li, Hongxin Zhao, Xiaoxing Yin and Mei Yang

Electronics 2020, 9(12), 2156; https://doi.org/10.3390/electronics9122156 - 16 Dec 2020

Cited by 5 | Viewed by 2394

Abstract

Direction finding and target tracking make demanding requirements on the measurement of incoming angles of electromagnetic waves. A monopulse antenna, based on the singular symmetric spoof surface plasmon polariton (SSPP) structure, is proposed for high-accuracy angle sensing. The singular SSPP structure is composed [...] Read more.

Direction finding and target tracking make demanding requirements on the measurement of incoming angles of electromagnetic waves. A monopulse antenna, based on the singular symmetric spoof surface plasmon polariton (SSPP) structure, is proposed for high-accuracy angle sensing. The singular SSPP structure is composed of periodic corrugated grooves for the confinement of the electromagnetic fields. Due to the microstrip–coplanar waveguide transition, the fields along both sides of the SSPP add constructively to form the endfire beam at the sum port and destructively to form the null radiation in the endfire direction at the difference port. An optimization based on the team progress algorithm is adopted to facilitate this antenna design. A prototype is designed and fabricated to validate the design principle, and measured results agree with the simulation. The proposed antenna shows a wide bandwidth ranging from 5.0 GHz to 7.5 GHz for both the sum and difference ports with the return loss greater than 10 dB, realizing a relative bandwidth of 40%. The isolation for the sum and difference ports is higher than 21 dB, and the null depth is larger than 20 dB over the entire operating range, which is favorable for the high accuracy angle sensing and measurement. This monopulse antenna has broad prospect in angle measuring systems such as direction finding and radar tracking scenes. Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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11 pages, 1888 KiB

Open AccessArticle

Evolutionary Optimization of Asymmetrical Pixelated Antennas Employing Shifted Cross Shaped Elements for UHF RFID

by Dominik Mair, Michael Renzler, Alexander Pfeifhofer and Thomas Ußmüller

Electronics 2020, 9(11), 1856; https://doi.org/10.3390/electronics9111856 - 05 Nov 2020

Cited by 9 | Viewed by 3531

Abstract

The design and optimization of antennas for specific boundary conditions and parameters, such as size and frequency, for a given application, is a highly complex and time consuming process, which usually involves elaborate computer-aided software packages and/or methods. Additionally, trade-offs and co-dependencies have [...] Read more.

The design and optimization of antennas for specific boundary conditions and parameters, such as size and frequency, for a given application, is a highly complex and time consuming process, which usually involves elaborate computer-aided software packages and/or methods. Additionally, trade-offs and co-dependencies have to be considered, when optimizing for a specific parameter, i.e., a high antenna gain goes usually hand-in-hand with a large antenna. Therefore, we implemented a method that involves the automated design and optimization of asymmetrical pixelated antennas using evolutionary algorithms, where arbitrary parameters can be optimized for chosen boundary conditions. In contrast to other approaches, shifted cross elements were employed as pixels to avoid point contact defects. We present results for antennas with an exemplary resonant frequency of 868 MHz and sizes of 3 × 3, 4 × 4 and 6 × 6 cm. The agreement between measurements and simulations for the antenna gain and reflection coefficient is excellent, with a maximum error of 1.15% for the single resonant frequency (relative error) and 1.35 dB for the antenna gain (mean absolute error). Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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12 pages, 4581 KiB

Open AccessArticle

Optimization of Log-Periodic TV Reception Antenna with UHF Mobile Communications Band Rejection

by Keyur K. Mistry, Pavlos I. Lazaridis, Zaharias D. Zaharis, Ioannis P. Chochliouros, Tian Hong Loh, Ioannis P. Gravas and David Cheadle

Electronics 2020, 9(11), 1830; https://doi.org/10.3390/electronics9111830 - 03 Nov 2020

Cited by 10 | Viewed by 4751

Abstract

The coexistence of TV broadcasting and mobile services causes interference that leads to poor quality-of-service for TV consumers. Solutions usually found in the market involve external band-stop filters along with TV reception log-periodic and Yagi-Uda antennas. This paper presents a log-periodic antenna design [...] Read more.

The coexistence of TV broadcasting and mobile services causes interference that leads to poor quality-of-service for TV consumers. Solutions usually found in the market involve external band-stop filters along with TV reception log-periodic and Yagi-Uda antennas. This paper presents a log-periodic antenna design without additional filtering that serves as a lower cost alternative to avoid interference from mobile services into the UHF TV. The proposed antenna operates in the UHF TV band (470–790 MHz-passband) and rejects the 800 MHz and 900 MHz bands (stopband) of 4G/LTE-800 and GSM900 services, respectively. Matching to 50 Ohms is very satisfactory in the passband with values of S11 below −12 dB. Furthermore, the antenna is highly directive with a realized gain of approximately 8 dBi and a front-to-back ratio greater than 20 dB. Full article

(This article belongs to the Special Issue Evolutionary Antenna Optimization)

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