Applied Sciences

Research

22 pages, 13879 KiB

Open AccessArticle

Novel Frequency-Reconfigurable Antennas with Ring Resonators and RF Switches: Enhancing Versatility and Adaptability in Wireless Communication Systems

by Duygu Nazan Gençoğlan, Merih Palandöken and Şule Çolak

Appl. Sci. 2023, 13(18), 10237; https://doi.org/10.3390/app131810237 - 12 Sep 2023

Cited by 2 | Viewed by 1002

Abstract

This study introduces innovative designs for frequency-reconfigurable antennas that utilize ring resonators combined with either PIN diodes or RF switches. These designs enhance the versatility, adaptability, and overall performance of the antennas in wireless communication systems. By controlling the switches and ring resonator, [...] Read more.

This study introduces innovative designs for frequency-reconfigurable antennas that utilize ring resonators combined with either PIN diodes or RF switches. These designs enhance the versatility, adaptability, and overall performance of the antennas in wireless communication systems. By controlling the switches and ring resonator, the antenna’s resonant frequencies and bandwidths can be adjusted, allowing for compatibility with various communication standards and frequency ranges. The proposed antenna exhibits four distinct operational states, each characterized by different resonance frequencies and operating frequency bands. Return loss, radiation pattern, radiation efficiency, and surface current distribution are analyzed for each state. State-1 (ON-ON) and State-2 (OFF-ON), which are characterized by resonance frequencies of 2.4 GHz and 3.33 GHz respectively, offer ranges suitable for Wi-Fi, Bluetooth, ISM, and IoT applications. State-3 (ON-OFF), with a resonance frequency of 3.0 GHz and bandwidth spanning from 2.59 GHz to 3.643 GHz, complies with Wi-Fi, Wi-Fi 6, and IoT requirements. State-4 (OFF-OFF) covers the band centered around 3.45 GHz. It is compatible with many applications such as 5G mid-band, Wi-Fi 6E, IoT, and cellular systems. The proposed antenna designs are versatile and compact since the overall antenna dimensions are 25 × 18 × 1.6 mm³. The radiation efficiency of the antenna configuration varies depending on operational states. By utilizing the advantages of both ring resonators and RF switches, the proposed antenna configurations offer new solutions that enhance their performance in wireless communication systems. This study compares the effects of using PIN diodes and SPDT switches on the performance of antennas and also examines the DC biasing effect on antenna characteristics. The simulation results are validated by the experimental analysis. The proposed antenna designs offer a new approach for wireless communication systems by using both ring resonators and RF switches. Full article

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

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11 pages, 4471 KiB

Open AccessCommunication

Quad-Band Uniformly Spaced Array Antenna Using Diverse Patch and Fractal Antennas

by Ilkyu Kim and Eunhee Kim

Appl. Sci. 2023, 13(6), 3675; https://doi.org/10.3390/app13063675 - 14 Mar 2023

Cited by 2 | Viewed by 1344

Abstract

Multi-band antennas have received significant interest because they can support multiple wireless communication services with a single antenna. However, an array antenna consisting of these element antennas can suffer from non-periodic arrangement due to the irregular sizes of the elements. In this paper, [...] Read more.

Multi-band antennas have received significant interest because they can support multiple wireless communication services with a single antenna. However, an array antenna consisting of these element antennas can suffer from non-periodic arrangement due to the irregular sizes of the elements. In this paper, various shapes of patch antennas with fractal antennas are used to ensure the periodic arrangement of the array antenna, and antenna array incorporated with a feed network is proposed. Four different antenna arrays operating at 2.45/3.7/4.3/5.0 GHz are aggregated in an antenna with interleaved disposition of the different element antennas. It is observed that mutual couplings between two elements are sufficiently low, at less than −23 dB. Peak antenna gain ranging from 11.1 dBi to 14.4 dBi at the four different bands is obtained. Full article

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

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16 pages, 8085 KiB

Open AccessArticle

Conceptual Design of a Semi-Dual Polarized Monopulse Antenna by Computer Simulation

by Ayodeji Matthew Monebi, Delger Otgonbat, Bierng-Chearl Ahn, Chan-Soo Lee and Jae-Hyeong Ahn

Appl. Sci. 2023, 13(5), 2960; https://doi.org/10.3390/app13052960 - 25 Feb 2023

Cited by 4 | Viewed by 1970

Abstract

Presented in this paper is a conceptual design by computer simulation of a monopulse reflector antenna with dual-circularly polarized sum patterns and linearly polarized azimuth and elevation difference patterns, which can be called a semi-dual polarized antenna. The proposed antenna consists of a [...] Read more.

Presented in this paper is a conceptual design by computer simulation of a monopulse reflector antenna with dual-circularly polarized sum patterns and linearly polarized azimuth and elevation difference patterns, which can be called a semi-dual polarized antenna. The proposed antenna consists of a five-element monopulse feed and a prime-focus parabolic reflector. The novelty of the proposed antenna is a monopulse feed consisting of a dual-circularly polarized square waveguide sum channel radiator and linearly polarized rectangular waveguide azimuth and elevation difference channel radiators. The separation of dual circular polarization is realized by a septum polarizer. The difference pattern is obtained by feeding two rectangular waveguides in opposite directions using a coaxial probe. The proposed monopulse feed geometry requires only two power combiners for a monopulse comparator network while providing dual-polarized performance comparable to the full dual-polarized sum and difference channel monopulse scheme. The concept of the proposed antenna is shown in a conceptual design by computer simulation. The monopulse feed is designed first, and then combined with a parabolic reflector. The designed monopulse reflector antenna operates at 14.5–16.0 GHz, and shows excellent sum and difference pattern characteristics: 36.1–36.7 dBc sum channel directivity with 0.65 dB boresight axial ratio and 32.6–32.9 dBi difference channel directivity with 1.56–1.66° crossover angle. Full article

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

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18 pages, 5717 KiB

Open AccessArticle

Theory of Edge Effects and Conductance for Applications in Graphene-Based Nanoantennas

by Tomer Berghaus, Touvia Miloh, Oded Gottlieb and Gregory Ya. Slepyan

Appl. Sci. 2023, 13(4), 2221; https://doi.org/10.3390/app13042221 - 9 Feb 2023

Cited by 2 | Viewed by 1521

Abstract

In this paper, we present a theory of edge effects in graphene for its applications to nanoantennas in the THz, infrared, and visible frequency ranges. The novelty of the presented model is reflected in its self-consistency, which is reached due to the formulation [...] Read more.

In this paper, we present a theory of edge effects in graphene for its applications to nanoantennas in the THz, infrared, and visible frequency ranges. The novelty of the presented model is reflected in its self-consistency, which is reached due to the formulation in terms of dynamical conductance instead of ordinary surface conductivity. The physical model of edge effects is based on using the concept of the Dirac fermion and the Kubo approach. In contrast with earlier well-known and widely used models, the surface conductance becomes non-homogeneous and non-local. The numerical simulations of the spatial behavior of the surface conductance were performed in a wide range of values, known from the literature, for the graphene ribbon widths and electrochemical potential. It is shown that if the length exceeds 800 nm, our model agrees with the classical Drude conductivity model with a relatively high degree of accuracy. For rather short lengths, the conductance exhibits a new type of spatial oscillations, which are not present in the ordinary conductivity model. These oscillations modify the form of effective boundary conditions and integral equations for electromagnetic field at the surface of graphene-based antenna. The developed theory opens a new way for realizing electrically controlled nanoantennas by changing the electrochemical potential via gate voltage. The obtained results may be applicable for the design of different carbon-based nanodevices in modern quantum technologies. Full article

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

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16 pages, 8818 KiB

Open AccessArticle

A Circularly Polarized mmWave Dielectric-Resonator-Antenna Array for Off-Body Communications

by Tarek S. Abdou, Rola Saad and Salam K. Khamas

Appl. Sci. 2023, 13(3), 2002; https://doi.org/10.3390/app13032002 - 3 Feb 2023

Cited by 4 | Viewed by 1861

Abstract

This paper presents a novel 28 GHz circularly polarized rectangular dielectric-resonator antenna (DRA) array for millimeter-wave (mmWave) off-body applications. A feed network incorporating cross slots was utilized in the rectangular DRA design to realize circular polarization (CP). In terms of the free-space wavelength, [...] Read more.

This paper presents a novel 28 GHz circularly polarized rectangular dielectric-resonator antenna (DRA) array for millimeter-wave (mmWave) off-body applications. A feed network incorporating cross slots was utilized in the rectangular DRA design to realize circular polarization (CP). In terms of the free-space wavelength, λ_o, the DRA dimensions were (0.48λ_o × 0.48λ_o × 0.27λ_o) at 28 GHz. The antenna array was simulated by incorporating dielectric layers with parameters that are equivalent to those of the human body at the desired frequency of 28 GHz for off-body communications. Moreover, the precise alignment and assembly of the DRA, which pose major difficulties at mmWave frequencies, were achieved by outlining the DRA positions on the ground plane using a three-dimensional (3D) printer. The array configuration was fabricated and measured with excellent performance, realizing a measured impedance bandwidth of 29% in conjunction with an axial-ration (AR) bandwidth of 13% and a broadside gain of 13.7 dBic at 28 GHz. Full article

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

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13 pages, 8729 KiB

Open AccessCommunication

A Wideband Eight-Element Antenna with High Isolation for 5G New-Radio Applications

by Jing Cai, Juhui Zhang, Shuqi Xi, Jianlin Huang and Gui Liu

Appl. Sci. 2023, 13(1), 137; https://doi.org/10.3390/app13010137 - 22 Dec 2022

Cited by 5 | Viewed by 1204

Abstract

A wideband multiple-input multiple-output (MIMO) antenna with high isolation for fifth-generation (5G) new-radio (NR) smartphone employment operating at a range from 3.3–5 GHz is presented in the paper. The wideband antenna is comprised of eight identical radiation units and applies defected ground structure [...] Read more.

A wideband multiple-input multiple-output (MIMO) antenna with high isolation for fifth-generation (5G) new-radio (NR) smartphone employment operating at a range from 3.3–5 GHz is presented in the paper. The wideband antenna is comprised of eight identical radiation units and applies defected ground structure (DGS) to offer higher isolation between antenna units. Each of the antenna elements is formed of a C-shaped microstrip line, two triangle-shaped strips and a rectangular strip. The measurement results present that the transmission coefficients of the presented antenna are smaller than −18 dB in the required wideband, and the envelope correlation coefficient (ECC) values are better than 0.005. The realized gain and efficiency of the designed antenna are about 3.5 dBi and higher than 75%, respectively. The volume of this total antenna is 150 × 75 × 7 mm³, and the measurement of each antenna unit is merely 6.8 mm × 7 mm × 0.8 mm (

0.077 λ \times 0.08 λ \times 0.009 λ

,

λ

is the wavelength of 3.4 GHz). The presented MIMO antenna is suitable for 5G new-radio (NR) smartphone applications. Full article

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

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10 pages, 3021 KiB

Open AccessCommunication

Multiband Frequency Tuneable Antennas for Selection Combining Strategy in White Space Applications

by Le-Huy Trinh and Fabien Ferrero

Appl. Sci. 2022, 12(21), 11062; https://doi.org/10.3390/app122111062 - 1 Nov 2022

Viewed by 1164

Abstract

This article presents a reconfigurable antenna using digitally tuneable capacitors (DTCs). Mounted on a 120 × 200 mm

^{2}

ground plane, the radiating element has very compact dimensions of 0.06

λ_{g}

× 0.016

λ_{g}

× 0.0016

λ_{g}

(with

λ_{g}

[...] Read more.

This article presents a reconfigurable antenna using digitally tuneable capacitors (DTCs). Mounted on a 120 × 200 mm

^{2}

ground plane, the radiating element has very compact dimensions of 0.06

λ_{g}

× 0.016

λ_{g}

× 0.0016

λ_{g}

(with

λ_{g}

being the wavelength at 585 MHz). The proposed structure could be operated in the white-space frequency band from 470 to 700 MHz. The antenna system is composed of two radiated elements that are placed at the corner of the board. The active components were soldered onto the antennas and controlled by an embedded microcontroller via the I2C interface. Antenna impedances were simulated and evaluated by measurement with an impedance-matching bandwidth of 39.32% (470–700 MHz) for an S11 less than −6 dB. Furthermore, the numerical results show a realized maximal gain ranging from −2.2 dBi at 470 MHz to 1.87 dBi at 700 MHz. Lastly, the diversity gains based on the radiation pattern of two resonators were calculated. The results show envelope correlation coefficient (ECC) values lower than 0.5 for the different configurations. Full article

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

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12 pages, 7060 KiB

Open AccessArticle

Dual-Band Multiple-Element MIMO Antenna System for Next-Generation Smartphones

by Saad Hassan Kiani, Mohamed Marey, Hüseyin Şerif SAVCI, Hala Mostafa, Umair Rafique and Muhammad Amir Khan

Appl. Sci. 2022, 12(19), 9694; https://doi.org/10.3390/app12199694 - 27 Sep 2022

Cited by 8 | Viewed by 1652

Abstract

This work presents a cost-effective multiple-element multiple-input multiple-output (MIMO) antenna system for next-generation smartphones. The proposed antenna system is developed on a 0.8 mm thin FR-4 substrate with a relative permittivity of 4.4, which consists of one main board and two sideboards. The [...] Read more.

This work presents a cost-effective multiple-element multiple-input multiple-output (MIMO) antenna system for next-generation smartphones. The proposed antenna system is developed on a 0.8 mm thin FR-4 substrate with a relative permittivity of 4.4, which consists of one main board and two sideboards. The dimensions of the main board and the two side boards are 150 × 75 mm² and 150 × 6 mm², respectively. The radiating elements are printed on the sideboards to provide space for other radio frequency (RF) components to be embedded on the main board. The proposed antenna resonates at two distinct allotted 5G bands, i.e., 3.5 GHz and 5.4 GHz, with impedance bandwidths of 200 MHz and 700 MHz, respectively. The isolation between the antenna elements is noted to be >18 dB and >12 dB for the 3.5 GHz and 5.4 GHz frequency bands. In addition, the proposed MIMO antenna provides pattern and spatial diversity characteristics in both bands with good gain and efficiency. Furthermore, the MIMO parameters such as envelope correlation coefficient (ECC), mean effective gain (MEG), and channel capacity (CC) are calculated, and it is observed that the MIMO antenna offers good diversity performance for the bands of interest. A prototype is fabricated and measured to verify the numerical data. The simulated results were discovered to be in excellent agreement with the measured results. It is also observed that the proposed MIMO antenna system holds promising features, and can be utilized for future generations of smartphones. Full article

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

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