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9 pages, 3098 KiB

Open AccessArticle

Terahertz Reconfigurable Planar Graphene Hybrid Yagi–Uda Antenna

by Qimeng Liu, Renbin Zhong, Boli Xu, Jiale Dong, Gefu Teng, Ke Zhong, Zhenhua Wu, Kaichun Zhang, Min Hu and Diwei Liu

Nanomaterials 2025, 15(7), 488; https://doi.org/10.3390/nano15070488 - 25 Mar 2025

Viewed by 494

Abstract

In this paper, we design a frequency reconfigurable antenna for terahertz communication. The antenna is based on a Yagi design, with the main radiating elements being a pair of dipole antennas printed on the top and bottom of a dielectric substrate, respectively. The [...] Read more.

In this paper, we design a frequency reconfigurable antenna for terahertz communication. The antenna is based on a Yagi design, with the main radiating elements being a pair of dipole antennas printed on the top and bottom of a dielectric substrate, respectively. The director and reflector elements give the antenna end-fire characteristics. The ends of the two arms of the dipole are constructed by staggered metal and graphene parasitic patches. By utilizing the effect of gate voltage on the conductivity of graphene, the equivalent length of the dipole antenna arms are altered and thereby adjust the antenna’s operating frequency. The proposed reconfigurable hybrid Yagi–Uda antenna can operate in five frequency bands separately at a peak gain of 4.53 dB. This reconfigurable antenna can meet the diverse requirements of the system without changing its structure and can reduce the size and cost while improving the performance. Full article

(This article belongs to the Special Issue 2D Structured Materials: Synthesis, Properties and Applications (2nd Edition))

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12 pages, 6370 KiB

Open AccessCommunication

A 24 GHz End-Fire Rod Antenna Based on a Substrate Integrated Waveguide

by Yanfei Mao, Shiju E, Yu Zhang and Wen-cheng Lai

Sensors 2025, 25(5), 1636; https://doi.org/10.3390/s25051636 - 6 Mar 2025

Cited by 1 | Viewed by 1136

Abstract

Most of the traditional rod antennas in the literature are in the shape of a cylinder or are conical, which are not suitable shapes for planar PCB technology or planar integrated CMOS or BiCMOS technology. In this paper, we present a 24 GHz [...] Read more.

Most of the traditional rod antennas in the literature are in the shape of a cylinder or are conical, which are not suitable shapes for planar PCB technology or planar integrated CMOS or BiCMOS technology. In this paper, we present a 24 GHz planar end-fire rod antenna based on an SIW (substrate integrated waveguide) suitable for planar PCB technology or planar integrated circuit technology. The antenna is made of PCB Rogers 4350 and utilizes the SIW to realize the end-fire rod antenna. The measurement results of the antenna are presented: its gain is 8.55 dB and its S11 bandwidth is 6.2 GHz. This kind of planar end-fire rod antenna possesses the characteristics of high gain, wide bandwidth, compactness, and simple design and structure. This type of antenna can also be used as a PCB antenna in other frequency bands, and it could also possibly be utilized in mm-wave and THz integrated antenna design in the future due to its very simple architecture. Full article

(This article belongs to the Special Issue Waveguide-Based Sensors and Applications)

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9 pages, 5592 KiB

Open AccessCommunication

Liquid Metal-Based Frequency and Pattern Reconfigurable Yagi Antenna for Pressure Sensing

by Xiaofeng Yang, Xiang Ma, Jiayi Yang, Yang Li, Meiping Peng and Qi Zheng

Sensors 2025, 25(5), 1498; https://doi.org/10.3390/s25051498 - 28 Feb 2025

Viewed by 895

Abstract

In this work, a frequency- and pattern-reconfigurable Yagi antenna based on liquid metal (LM) switches is proposed for pressure sensing and health monitoring. The proposed antenna consists of a dipole radiator, a reflector, a director, a dielectric substrate, and four flexible LM switches. [...] Read more.

In this work, a frequency- and pattern-reconfigurable Yagi antenna based on liquid metal (LM) switches is proposed for pressure sensing and health monitoring. The proposed antenna consists of a dipole radiator, a reflector, a director, a dielectric substrate, and four flexible LM switches. Benefitted from the switching effect of the LM switches under external pressure, the frequency and radiation pattern of the antenna can be reconfigured. When the LM switch is fully or partially turned on, the radiation directions of the antenna are bidirectionally end-shot and end-fired, respectively. The operating frequency of the antenna can be tuned from 2.28 GHz to 2.5 GHz. It is shown that a maximum gain of 6 dBi can be obtained. A sample was fabricated and measured, and the experimental results were in good agreement with the simulations. The reconfigurable antenna can be applied in wireless pressure-sensing and health-monitoring systems. Full article

(This article belongs to the Section Communications)

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14 pages, 9498 KiB

Open AccessArticle

Electromagnetic Absorber-Embedded Ka-Band Double-Layer Tapered Slot Antenna for the Reduced Radar Cross Section at X-Band

by Wonkyo Kim, Youngwan Kim, Hee-Duck Chae, Jihan Joo, Jun-Beom Kwon and Ick-Jae Yoon

Appl. Sci. 2025, 15(5), 2507; https://doi.org/10.3390/app15052507 - 26 Feb 2025

Cited by 1 | Viewed by 588

Abstract

An electromagnetic (EM) absorber-embedded Ka-band double-layer tapered slot antenna (DLTSA) is proposed in this work. The EM absorber is placed on both sides of the tapered radiating slots as a means of achieving the reduced monostatic radar cross section (RCS) at the X-band. [...] Read more.

An electromagnetic (EM) absorber-embedded Ka-band double-layer tapered slot antenna (DLTSA) is proposed in this work. The EM absorber is placed on both sides of the tapered radiating slots as a means of achieving the reduced monostatic radar cross section (RCS) at the X-band. A conventional tapered slot antenna (TSA) with EM absorbers at the same position suffers from the distorted current distribution from the feedline to the radiating slots and causes a degraded radiation performance with a tilted beam. In contrast, the DLTSA with EM absorbers maintains the impedance and radiation characteristics of the antenna without the EM absorbers, while achieving the reduced monostatic RCS for the cross-polarized incident wave. The functionality of the reduced RCS is verified with the 4-by-4 DLTSA array design. The 4-by-4 array prototype with FGM-125 EM absorbers is matched at the Ka-band with a 14.7 dBi boresight gain at 35 GHz. The monostatic RCS is measured in an indoor environment, showing 6.5 dB monostatic RCS reduction at the X-band on average, verifying the computed expectations. This work validates the possible use of EM absorbers at the front side of a missile seeker composed of end-fire radiating elements. Full article

(This article belongs to the Special Issue Multi-Band/Broadband Antenna Design, Optimization and Measurement)

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15 pages, 8083 KiB

Open AccessArticle

Advanced Metamaterial-Integrated Dipole Array Antenna for Enhanced Gain in 5G Millimeter-Wave Bands

by Domin Choi, Md Abu Sufian, Jaemin Lee, Wahaj Abbas Awan, Young Choi and Nam Kim

Appl. Sci. 2024, 14(19), 9138; https://doi.org/10.3390/app14199138 - 9 Oct 2024

Cited by 3 | Viewed by 2249

Abstract

A metamaterial-based non-uniform dipole array antenna is presented for high gain 5G millimeter-wave applications with a wideband characteristic. Initially, a non-uniform dipole array is designed on a 0.202 mm thick Rogers RO4003C substrate, offering a wide operating bandwidth ranging from 23.1 GHz to [...] Read more.

A metamaterial-based non-uniform dipole array antenna is presented for high gain 5G millimeter-wave applications with a wideband characteristic. Initially, a non-uniform dipole array is designed on a 0.202 mm thick Rogers RO4003C substrate, offering a wide operating bandwidth ranging from 23.1 GHz to 44.8 GHz. The dipole array antenna emits unidirectional end-fire radiation with a maximum gain of 8.1 dBi and an average gain of 6.7 dBi. Subsequently, to achieve high gain performance, a 5 × 7 metamaterial structure is designed in the direction of the antenna radiation. The implemented metamaterial structure is optimized for the operating frequency, enhancing the directivity of the antenna radiation and resulting in a gain increment of more than 3 dBi compared to the dipole array alone. The developed metamaterial-integrated dipole array antenna offers an operating bandwidth (S11 < −10 dB) of more than 21 GHz (63.92%), ranging from 23.1 GHz to 44.8 GHz, covering the most commonly used 5G millimeter-wave frequency bands (n257, n258, n259, n260, and n261). Furthermore, the presented antenna yields a stable high gain with a peak gain of 11.21 dBi and a good radiation efficiency of more than 64%. The proposed antenna is an excellent option for millimeter-wave 5G systems due to its overall properties, particularly its high gain and end-fire radiation characteristics, combined with a wide operating bandwidth. Full article

(This article belongs to the Section Electrical, Electronics and Communications Engineering)

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11 pages, 4901 KiB

Open AccessArticle

A Metamaterial Bandpass Filter with End-Fire Coaxial Coupling

by Xianfeng Tang, Yemin Zang, Xiangqiang Li and Che Xu

Electronics 2024, 13(16), 3158; https://doi.org/10.3390/electronics13163158 - 10 Aug 2024

Cited by 1 | Viewed by 1233

Abstract

A miniaturized metamaterial (MTM) bandpass filter (BPF) based on end-fire coaxial coupling is proposed. End-fire coaxial coupling is achieved by using the coaxial cavity to connect with the SubMiniature version A connector. The subwavelength characteristics of the MTM lead to the miniaturization advantages [...] Read more.

A miniaturized metamaterial (MTM) bandpass filter (BPF) based on end-fire coaxial coupling is proposed. End-fire coaxial coupling is achieved by using the coaxial cavity to connect with the SubMiniature version A connector. The subwavelength characteristics of the MTM lead to the miniaturization advantages of the filter in transverse dimensions. Moreover, the longitudinal length of the coaxial cavity can be sharply reduced by introducing matched blocks. As a result, the proposed filter has miniaturization merit both in transverse and longitudinal dimensions. The full-wave simulation results further reveal that the MTM BPF exhibits the advantages of low loss, low reflection, and low group delay. Additionally, the fractional bandwidth is approximately 13% when |S₁₁| is less than −15 dB. The MTM BPF might have potential applications to array antennas for easily being expanded to two dimensional arrays. Full article

(This article belongs to the Special Issue Electrical Power Systems Quality)

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14 pages, 19193 KiB

Open AccessArticle

A Radiation-Pattern Reconfigurable Antenna Array for Vehicular Communications

by Feng Gao and Hucheng Sun

Sensors 2024, 24(13), 4136; https://doi.org/10.3390/s24134136 - 26 Jun 2024

Cited by 4 | Viewed by 1793

Abstract

This paper presents a low-profile reconfigurable antenna array capable of five radiation-pattern modes for vehicular communication applications. The antenna array consists of four antenna elements, each containing four square patches. Exciting one of the square patches generates a broadside radiation. A square parasitic [...] Read more.

This paper presents a low-profile reconfigurable antenna array capable of five radiation-pattern modes for vehicular communication applications. The antenna array consists of four antenna elements, each containing four square patches. Exciting one of the square patches generates a broadside radiation. A square parasitic patch is added at the rear of the excited patch, and two square parasitic patches are placed at the front. By optimizing the design of these parasitic patches, including the treatment of center slotting and addition of shorting pins, the antenna element achieves an end-fire beam with a certain tilt angle. On this basis, a reconfigurable feeding network is designed with 1:1 and 1:4 output modes. By connecting the reconfigurable feeding network to the four antenna elements and altering the on/off states of the PIN diodes in the feeding network, a reconfigurable antenna with four end-fire beams and one omnidirectional beam in its radiation pattern is realized. Measurement results demonstrate an excellent impedance bandwidth, radiation pattern, and gain performance in all modes. The four end-fire and one omnidirectional radiation characteristics make it highly suitable for vehicular communication applications. Full article

(This article belongs to the Special Issue Novel Antennas for Wireless Communication and Intelligent Sensing)

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13 pages, 3290 KiB

Open AccessArticle

A Bidirectional Quasi-Endfire Patch Antenna with Low Elevation Angle

by Ziling Zhou, Jin Shi, Gu Liu, Kai Xu and Ruirui Jiang

Micromachines 2024, 15(6), 777; https://doi.org/10.3390/mi15060777 - 12 Jun 2024

Cited by 1 | Viewed by 1405

Abstract

A bidirectional quasi-endfire patch antenna with a low elevation angle has promising applications for wireless communication systems that are vehicle-based, airborne, and shipborne. In this paper, the shortened patch resonators and open patch resonator are integrated to form a bidirectional quasi-endfire patch antenna [...] Read more.

A bidirectional quasi-endfire patch antenna with a low elevation angle has promising applications for wireless communication systems that are vehicle-based, airborne, and shipborne. In this paper, the shortened patch resonators and open patch resonator are integrated to form a bidirectional quasi-endfire patch antenna with low elevation angle. The open patch resonator operates with a TM₂₀ mode to realize bidirectional radiation. The two shortened patch resonators operate with a TM₀₁ mode coupled with a TM₂₀ mode to control the phase difference between them at a suitable angle, so that the shortened patch resonators act as directors to tilt the dual beams toward the endfire direction and achieve low elevation angle. Compared with reported patch antennas with dual beams, the proposed antenna has the lowest elevation angle and a compact structure. For demonstration purposes, an antenna prototype operating at 3.5 GHz is fabricated and measured, exhibiting a low elevation angle of ±28°, a −10 dB impedance matching bandwidth from 3.44 GHz to 3.61 GHz, and a size of 1.36 λ₀ × 0.57 λ₀ with a profile of 0.036 λ₀. A prototype with two pair of shortened patch directors further reduces the elevation angle to ±19° with the size of 2.3 λ₀ × 0.57 λ₀. Full article

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11 pages, 3972 KiB

Open AccessArticle

Folded Narrow-Band and Wide-Band Monopole Antennas with In-Plane and Vertical Grounds for Wireless Sensor Nodes in Smart Home IoT Applications

by Mohammad Mahdi Honari, Seyed Parsa Javadi and Rashid Mirzavand

Electronics 2024, 13(12), 2262; https://doi.org/10.3390/electronics13122262 - 8 Jun 2024

Cited by 1 | Viewed by 1454

Abstract

This article presents two monopole antennas with an endfire radiation pattern in the UHF band that can be installed on dry walls or metallic cabinets as a part of wireless sensor nodes, making them a suitable choice for smart home applications, such as [...] Read more.

This article presents two monopole antennas with an endfire radiation pattern in the UHF band that can be installed on dry walls or metallic cabinets as a part of wireless sensor nodes, making them a suitable choice for smart home applications, such as the wireless remote control of house appliances. Two different antennas are proposed to cover the RFID bands of North America (902–928 MHz) and worldwide (860–960 MHz). The antennas have wide horizontal radiation patterns that provide great reading coverage in their communication with a base station placed at a certain distance from the antennas. The structures have two ground planes, one in-plane and the other vertical. The vertical ground helps the antenna to have a directive radiation and also makes it easily installed on walls. The antenna feeding line lies over the vertical ground substrate. The maximum dimensions of the narrow-band antenna are L × W = 0.3

λ \times

0.14

λ

, and those for the wide-band antenna are L × W = 0.39

λ \times

0.14

λ

. The measured results show that the bandwidth of the proposed antennas for the North America and worldwide RFID bands are from 902 MHz to 939 MHz and 822 MHz to 961 MHz, with maximum gains of 4.2 dBi and 4.9 dBi, respectively. Full article

(This article belongs to the Special Issue Antenna Design and Its Applications)

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20 pages, 14972 KiB

Open AccessArticle

A Compact MIMO Antenna Based on Modal Analysis for 5G Wireless Applications

by Parveez Shariff Bhadravathi Ghouse, Deepthi Mariam John, Pallavi R. Mane, Debdeep Saha, Supreetha Balavalikar Shivarama, Sameena Pathan, Bharathi Raghavendra Bhat, Shweta Vincent and Tanweer Ali

Micromachines 2024, 15(6), 729; https://doi.org/10.3390/mi15060729 - 30 May 2024

Cited by 6 | Viewed by 1369

Abstract

This article presents a planar, non-angular, series-fed, dual-element dipole array MIMO antenna operating at 28 GHz with the metasurface-based isolation improvement technique. The initial design is a single-element antenna with a dual dipole array which is series-fed. These dipole elements are non-uniform in [...] Read more.

This article presents a planar, non-angular, series-fed, dual-element dipole array MIMO antenna operating at 28 GHz with the metasurface-based isolation improvement technique. The initial design is a single-element antenna with a dual dipole array which is series-fed. These dipole elements are non-uniform in shape and distance. This dipole antenna results in end-fire radiation. The dipole antenna excites the

J_{1}

mode for its operation. Further, with the view to improve channel capacity, the dipole array expands the antenna to a three-element MIMO antenna. In the MIMO antenna structure, the sum of the

J_{1}

,

J_{2}

, and

J_{3}

modes is excited, causing resonance at 28 GHz. This article also proposes a metasurface structure with wide stopband characteristics at 28 GHz for isolation improvement. The metasurface is composed of rectangle-shaped structures. The defected ground and metasurface structure combination suppresses the surface wave coupling among the MIMO elements. The proposed antenna results in a bandwidth ranging from 26.7 to 29.6 GHz with isolation improvement greater than 21 dB and a gain of 6.3 dBi. The antenna is validated with the diversity parameters of envelope correlation coefficient, diversity gain, and channel capacity loss. Full article

(This article belongs to the Special Issue Advanced Antenna System: Structural Analysis, Design and Application)

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12 pages, 3736 KiB

Open AccessArticle

A Low-Cost Printed Log-Periodic Dipole Array for DVB-T2 Digital TV Applications

by Giovanni Andrea Casula, Giacomo Muntoni, Paolo Maxia and Giorgio Montisci

Appl. Sci. 2024, 14(1), 451; https://doi.org/10.3390/app14010451 - 4 Jan 2024

Viewed by 1856

Abstract

A printed log-periodic dipole array (LPDA) for DVB-T2 Digital TV applications, covering the whole DVB-T2 UHF band from Channel 21 to Channel 69 (470 MHz–860 MHz), is presented. The presented antenna offers a compact size and a lower cost compared to both wire [...] Read more.

A printed log-periodic dipole array (LPDA) for DVB-T2 Digital TV applications, covering the whole DVB-T2 UHF band from Channel 21 to Channel 69 (470 MHz–860 MHz), is presented. The presented antenna offers a compact size and a lower cost compared to both wire and similar printed LPDAs, with a normalized area of only 0.26 λ² (where λ is the free-space wavelength at the central frequency) and a similar (or higher) average gain. It is composed of meandered radiating dipoles, and it is implemented on FR4, the cheapest dielectric substrate available on the market. Moreover, the antenna size has been reduced to an A4 sheet dimension (210 mm × 297 mm) to cut down the production cost. The antenna has been designed starting from Carrel’s theory and using a general-purpose 3D CAD, CST Studio Suite. The results show that the proposed antenna can be used for broadband applications (≈74% bandwidth) in the whole operating frequency band of Digital TV, with a satisfactory end-fire radiation pattern, a stable gain, and a radiation efficiency over the required frequency range (average values 6.56 dB and 97%, respectively). Full article

(This article belongs to the Special Issue Editorial Board Members' Collection Series: Electromagnetics and Communication)

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15 pages, 6069 KiB

Open AccessArticle

Metamaterial-Based Series-Fed Antenna with a High Gain and Wideband Performance for Millimeter-Wave Spectrum Applications

by Bashar A. F. Esmail, Slawomir Koziel and Dustin Isleifson

Electronics 2023, 12(23), 4836; https://doi.org/10.3390/electronics12234836 - 30 Nov 2023

Cited by 1 | Viewed by 2349

Abstract

This paper presents a high-gain, wideband series-fed antenna designed for 5G millimeter-wave (MMW) applications. The structure employs a substrate-integrated-waveguide (SIW)-based power splitter and metamaterials (MMs). The power divider functions effectively at 27.5 GHz, exhibiting an impedance bandwidth from 26.9 to 28.6 GHz. The [...] Read more.

This paper presents a high-gain, wideband series-fed antenna designed for 5G millimeter-wave (MMW) applications. The structure employs a substrate-integrated-waveguide (SIW)-based power splitter and metamaterials (MMs). The power divider functions effectively at 27.5 GHz, exhibiting an impedance bandwidth from 26.9 to 28.6 GHz. The series-fed dipole is assembled on the SIW-based power splitter, incorporating four dipoles with varying lengths and spacing. The dipoles are connected in series on both sides, running in parallel through a microstrip line. Effectively combining the resonances of the series-fed dipoles and the SIW results in a broad impedance bandwidth, ranging from 26.9 GHz to 34.75 GHz. The design has a gain extending from 9 to 10.5 dBi within the operating bandwidth. To improve gain performance without a substantial increase in antenna size, 11 × 6 MM unit cells were positioned in front of the antenna. As a result, the proposed antenna achieves a maximum gain of 14.1 dBi at 30.5 GHz while maintaining an operational bandwidth of 7.85 GHz. Additionally, due to the arrangement of the two MM-based series-fed dipoles, the antenna exhibits symmetrical dual-beam E-plane radiation at ±20° and 28 GHz in the end-fire direction. The developed system was experimentally validated and an excellent agreement between the simulated and measured data was demonstrated. Full article

(This article belongs to the Section Microwave and Wireless Communications)

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12 pages, 5131 KiB

Open AccessCommunication

A Printed Dipole Array with Bidirectional Endfire Radiation for Tunnel Communication

by Tianfan Xu, Mengchi Xu, Haitao Lu and Xiao Cai

Sensors 2023, 23(22), 9137; https://doi.org/10.3390/s23229137 - 13 Nov 2023

Viewed by 1355

Abstract

Tunnel communication always suffers from path loss and multipath effects caused by surrounding walls. Meanwhile, the traditional leaky coaxial cables are expensive to deploy, inconvenient to operate, and difficult to maintain, leading to many problems in practical use. To solve the abovementioned problems, [...] Read more.

Tunnel communication always suffers from path loss and multipath effects caused by surrounding walls. Meanwhile, the traditional leaky coaxial cables are expensive to deploy, inconvenient to operate, and difficult to maintain, leading to many problems in practical use. To solve the abovementioned problems, a low-profile printed dipole array operating at 3.5 GHz with bidirectional endfire radiation is designed based on the method of maximum power transmission efficiency (MMPTE). By setting two virtual test receiving dipoles at the two opposite endfire directions and then maximizing the power transmission efficiency between the printed dipole array to be designed and the test receiving antennas, the optimal amplitudes and phases for the array elements are obtained. Based on the optimal distributions of excitations, the simulation results show that the proposed eight-element printed dipole array can simultaneously generate two mirrored endfire beams towards opposite directions. Furthermore, the corresponding normalized cross-polarization levels are lower than −22.3 dBi both in the azimuth and elevation planes. The peak endfire gain is 10.7 dBi with maintenance of higher than 10 dBi from 3.23 GHz to 3.66 GHz, which is suitable for tunnel communication. Full article

(This article belongs to the Special Issue Microwave Communication and Signal Transmission Based on Antennas and Metamaterials)

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12 pages, 4428 KiB

Open AccessArticle

Designing a Compact Filtering Quasi-Yagi Antenna with Multiple Radiation Nulls Using Embedded Resistor-Loaded Arms

by Lipeng Zhai, Yi Guo, Zongming Xu, Xuefeng Zhang, Yanyun Chen and Jin Shi

Micromachines 2023, 14(7), 1445; https://doi.org/10.3390/mi14071445 - 19 Jul 2023

Cited by 4 | Viewed by 2086

Abstract

In this paper, a compact quasi-Yagi antenna with embedded resistor-loaded arms is proposed to obtain a filtering response with four radiation nulls. The embedded resistor-loaded arms achieve two additional radiation nulls caused by reverse currents and absorb the unwanted out-of-band resonant points brought [...] Read more.

In this paper, a compact quasi-Yagi antenna with embedded resistor-loaded arms is proposed to obtain a filtering response with four radiation nulls. The embedded resistor-loaded arms achieve two additional radiation nulls caused by reverse currents and absorb the unwanted out-of-band resonant points brought by themselves. The director close to the driver provides a resonant point and a radiation null caused by opposite currents between the driver and the director. Compared with other filtering quasi-Yagi antennas, the proposed one can achieve a filtering response with a compact size along the endfire direction. For demonstration, a balun-integrated prototype covering the 5G band N78 (3.3–3.8 GHz) is designed with the size along the endfire direction (without ground) of 0.13 λ₀ (λ₀ is the wavelength in the free space at center frequency), and the measured results show a 10 dB impedance-matching bandwidth of 22.9% (3.21–4.04 GHz), four radiation nulls, and a peak gain of 4.73 dBi. Full article

(This article belongs to the Special Issue New Trends in Microwave/Millimeter Antennas/Filters: From Fundamental Research to Applications)

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14 pages, 5695 KiB

Open AccessTechnical Note

A VHF Circularly Polarized Turnstile Antenna with Balun for Meteor Radar

by Wei Qiao, Chen Zhou, Wenjie Yin, Mingjie Lv and Zhengyu Zhao

Remote Sens. 2023, 15(8), 2058; https://doi.org/10.3390/rs15082058 - 13 Apr 2023

Cited by 2 | Viewed by 3781

Abstract

This paper presents a circularly polarized turnstile antenna for a meteor radar system. The antenna employs a pair of turnstile radiators, a 1:2 power divider and a 90° phase shifter. After a series of simulations and optimizations, the maximum circularly polarized gain at [...] Read more.

This paper presents a circularly polarized turnstile antenna for a meteor radar system. The antenna employs a pair of turnstile radiators, a 1:2 power divider and a 90° phase shifter. After a series of simulations and optimizations, the maximum circularly polarized gain at 39 MHz is 5.9 dBic with 96° 3 dB beam width. The simulated axial ratio below 3 dB is from −39° to 39° within the band of interest. Then, the proposed antenna is fabricated and applied to a meteor radar system. Two tests are carried out for radiation characteristics demonstration. In the first test, the VSWR of the proposed antenna is below 1.2 at 38.5–39.5 MHz and keeps good agreement with simulation results. However, the meteor azimuth distribution is illogical when the output results are compared with the Australian meteor detection radar (ATRAD) meteor detection. To address the problem, baluns are investigated and introduced for balanced feeding. The 1:1 unbalance–balance transformer has been used to improve the radiation characteristics of the designed antenna. The final test results show that the meteor radar system with the improved antenna achieves better performances in meteor counts and meteor azimuth distribution. Full article

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