Antenna Components Research Articles

Optimization of Graphene-based Antenna using Metasurface for THz Applications using Ensemble Learning models

Aims and Background: These days, communication is governed by scaled-down devices with extremely high data transfer rates. The days of data transfer rates in megabytes are long gone and the systems are touching data speeds of hundreds of gigabytes. To cater to this requirement, the evolution of metasurface-based antennas working in the THz frequency range is gaining pace. Objectives and Methodology: Metasurface layers in antennas have unique mechanical and electrical properties that make them feasible. Graphene is a preferred metasurface material when designing antennas. In this paper, two novel designs of graphene-based metasurface antennas are proposed. These patch antennas with graphene metasurface layers have two configurations for slotted patches. Both graphene and gold-slotted patches are tested in this paper, and results are presented and validated for various performance parameters like return loss, peak gain, peak directivity, and radiation efficiency. Results: The design of the proposed Graphene Patch Antennas (GPA) is done in HFSS, and once the design is complete, the data is collected for variations in antenna parameters and is further processed via machine learning for better convergence in terms of return loss using ensemble learning. Optimal tuning of antenna components like substrate length, patch length, slot width, etc., is done using two regressor algorithms viz Histogram-based Gradient Boosting Regression Tree (HBDT) and Random Forest Tree (RFT) in machine learning. The radiation efficiencies of the two designs presented in this work are 89.04%, 97.54%, an average radiation efficiency of of 93.29%. The bandwidth of the two antenna designs is 8.63 THz and 8.69 THz, respectively. Conclusion: Experimental results indicate that the proposed designs are achieved better bandwidth, and radiation efficiencies compared to state-of-art designs.

A 2.4-7GHz Dual Band Microstrip Patch Antenna (DBMPA)

We designed a 2.4-7GHz dual-band microstrip patch antenna DB-MPA using electromagnetic field simulation and transmission characteristic (S21) measurements. Optimizing the slot length of the patch surface increased the directional antenna gain at 7 GHz by 3.5 dB compared to 2.48 GHz, reducing the effect of the higher spatial propagation loss of 9 dB at 7 GHz. A transmission system simulation with an antenna component model incorporating S21 data measured with the 2.4-7GHz DB-MPA from 1 to 8 GHz was conducted at a spatial propagation distance of 5 to 40 m to verify the practicality of the 2.4-7GHz DB-MPA

A novel asymmetric antipodal Vivaldi MIMO antenna

This communication describes the development and assessment of the genuine Antipodal Vivaldi MIMO antenna operating in the ultra-wideband spectrum. FR4 dielectric material, which is widely used in antenna designs and has characteristic features, is selected and used as a dielectric. The single antenna component has two asymmetric flares obtained with different parameters, and it also has a rectangular ground plane combined with a bottom flare. In the MIMO configuration, the single-antenna is built in a rotationally orthogonal way to generate a four-port system with the dimensions of 45 × 45 × 1 mm3. The vertical and horizontal stubs are added to the ground flare to obtain a common ground structure and increase the performance of the novel antenna design. It has a bandwidth of approximately 9 GHz, which starts from 2.85 GHz and ends at 11.8 GHz. The antenna has reasonable gain values and a high isolation value between the elements in the operation range. In this context, it is foreseen that the developed structure can be utilized in distinct multiport UWB applications.

Dual-band millimetre wave MIMO antenna with reduced mutual coupling based on optimized parasitic structure and ground modification

In this study, a high-isolation dual-band (28/38 GHz) multiple-input–multiple-output (MIMO) antenna for 5G millimeter-wave indoor applications is presented. The antenna consists of two interconnected patches. The primary patch is connected to the inset feed, while the secondary patch is arc-shaped and positioned over the main patch, opposite to the feed. Both patches function in the lower 28 GHz band, while the primary patch is accountable for inducing the upper 38 GHz band. An expedited trust-region (TR) algorithm is employed to optimize the dimensions of the antenna components, ensuring the antenna operates efficiently with high reflection at both bands. The antenna demonstrates a gain exceeding 7 dBi at both frequencies. An array of four antennas is configured orthogonally to create a MIMO system with isolation surpassing 19 dB. The isolation is further enhanced through the addition of a circular parasitic patch at the front and modifications made to the ground. The TR method is employed again to optimize their parameters and achieve the desired isolation, exceeding 32 dB at both bands. The MIMO system demonstrates outstanding diversity performance at both frequencies, characterized by low values of the envelope correlation coefficient (ECC) (< 10 − 4), channel capacity loss (CCL) (< 0.03 bit/s/Hz), and total active reflection coefficient (TARC) (< − 10 dB). Additionally, it secures a diversity gain (DG) exceeding 9.99 dB. The MIMO system is manufactured and tested, showing good alignment between simulation and measurement data for all performance metrics.

A four-port self-multiplexing tunable graphene based dielectric resonator antenna with defective ground structure for high isolation and MIMO capabilities

Objectives and designA novel self-multiplexing terahertz antenna with four tunable ports is proposed in this work. The configuration comprises four rectangular dielectric resonators (DRs) affixed to a substrate, which are excited through L-shaped microstrip-fed slots positioned beneath them. To guarantee efficient isolation among the tunable antenna components, periodic unit cells are introduced into the ground plane, forming a defective ground structure (DGS). Each L-shaped slot element is equipped with a graphene strip to regulate the tunability of each DR element. Results and applicationsThis antenna can operate in various modes with resonant frequencies at 4.01, 4.23, 4.37, and 4.57 THz. It holds potential for future terahertz wireless applications that require the utilization of adjacent channels with distinct communication frequencies. Furthermore, a four-port antenna design is implemented, offering tunable MIMO capabilities with self-quadruplexing ability. The MIMO parameters, specifically the envelope correlation coefficient (ECC) and diversity gain (DG), have been assessed and found to fall within acceptable limits across the operating frequency bands. Additionally, an equivalent circuit model (ECM) is analysed to shed light on the antenna's working principle and verify the obtained results.

A patch-antenna-based smart aggregate for passive strain sensing in concrete

This paper presents an innovative smart aggregate based on passive patch antenna. The designed unstressed patch antenna components which can move relatively serves as a sensing unit, and the sensing unit can be embedded in concrete to form smart aggregates for strain sensing after encapsulation. The study investigates the influence of different encapsulation materials and external environments on the electromagnetic parameters of the patch antenna sensing unit within the smart aggregate. Furthermore, it establishes the theoretical relationship between the resonant frequency of the sensing unit and the deformation of concrete. When using shielding material to encapsulate the patch antenna, it can avoid the influence of external dielectric environment variation; when using non-shielding materials to encapsulate the patch antenna, external environmental sensing can be achieved. Simulations and experimental tests were used to study the characteristics of two different encapsulation methods. Two patch-antenna-based smart aggregates with different dielectric substrates, Rogers RT5880 and Rogers RO3010, were fabricated, which can be embedded inside the concrete and realize the passive sensing of the internal strain of the concrete. The fabricated smart aggregates no longer require continuous power supply, thus having better applicability. Experimental tests were undertaken to demonstrate the viability of the proposed patch-antenna-based smart aggregate. The sensing sensitivities of the proposed smart aggregates based on patch antennas with dielectric substrates Rogers RO3010 and Rogers RT5880 were 1.219 MHz/100 με and 0.598 MHz/100 με, respectively.

Design, kinematics and dynamic analysis of a novel double – scissors link deployable mechanism for space antenna truss

A novel truss deployable mechanism composed of scissors links is proposed in this paper. First, the geometry analysis of the general single modular unit of truss deployable antenna and the construction of the planar double scissors link mechanism module is conducted. The entire antenna is prepared by connecting the single module in a circular configuration. Using the Gruebler's method, the mobility of the double scissors link truss deployable module is proved equals to 1. Furthermore, based on the Newtonian approach, kinematic characteristics of the double scissors link truss deployable mechanism are examined. The velocities and accelerations of the antenna components obtained analytically are validated through simulations in MATLAB, SolidWorks and ADAMS. In addition to this, the forces, torques and bearing stresses involved in various struts and joints are calculated to ensure that the operation is within the yield limits. The dynamic characteristics of the antenna i.e., acceptable natural frequency is calculated by developing a 10 DoF vibration model. The analytical equations are solved using MATLAB, and the results are validated through simulations in ANSYS Workbench. The novel antenna assembly gives the natural frequency response of 0.0652 Hz with a 1.6 % error. The proposed double scissors link truss deployable mechanism shows storage ratio of 1 and 10.2 along vertical and radial directions respectively. The dynamic response and storage ratio of novel assembly is validated with results in literature. The research lays the foundation for the kinematics and dynamics analysis of other space deployable mechanisms.

Isolation enhancement of a two- orthogonal printed elliptical slot MIMO antenna array with EBG structure for millimeter wave 5G applications

This work investigates a high-isolation Orthogonal Printed Elliptical Slot Antenna (OPESA) array with Multiple Inputs and Multiple Outputs (MIMO). A unique composite Electromagnetic Band-Gap (EBG) structure consisting of a vertical six rings positioned between single element antennas were devised and investigated with the aim of reducing mutual interaction between antenna components. A distinct feeble electric field that could successfully inhibit the Mutual Coupling (MC) among the antenna components is easily produced by the suggested composite EBG construction. One type of decoupling constructions throughout the antenna growth was carefully examined at together the theoretical and physical levels in order to offer a clear representation of the suggested antenna array’s design concept and decoupling technique. The antenna array design process was cleverly separated into three stages. In order to verify the suggested decoupling idea, the array Scheme was constructed, assessed, and measured. Studying the antenna gain, radiation pattern, and reflection coefficient, it was found that the simulated and measured findings were very consistent. According to the models, the array has an extreme radiation efficiency of about 91%, a minor value of Envelope Correlation Coefficient (ECC < 1.8 × 10−4), and a maximal gain of 11.5 dBi. The electrical size, highest isolating grade and the recommended MIMO antenna’s 90 dB isolating bandwidth (BW) were assessed. The planned antenna has several appealing features that set it apart from previous similar designs. These features include a low design complexity, a great Diversity Gain rate (DG > 9.99 dB), the BW of the proposed antenna extends from 25 GHz to more than 40 GHz, an enormously great isolation level (about 90 dB), and compressed dimensions (51 mm × 30 × 1.6 mm). For verifying the recommended antenna for MIMO. the suggested MIMO antenna design’s radiation efficiency, a thorough time-domain study is suggested.

A Ka-Band Two-Channel Two-Beam Receiver Based on a Substrate-Integrated Suspended Line

To realize the miniaturization and high performance for the key transceiver components of a phased array antenna, we proposed a two-channel two-beam receiver based on a substrate-integrated suspended-line (SISL). Multi-layer composite substrate printing circuit is used in the SISL structure to replace the metal cavity and passive circuits. The active components are placed in the air cavity in the SISL structure. The substrates forming the cavity are soldered together to ensure the hermetic seal and high performance. The SISL circuits have the advantage of low loss, low cost, light weight, self-packaging, and high inter-channel isolation. The proposed Ka-band two-channel two-beam receiver shows a gain of &gt;28 dB, a noise figure of &lt;2.6 dB, with functions of 6-bit phase shifting and attenuation.

A high sensitivity planar electric–magnetic isolated sensor for full characterization of magneto-dielectric materials

Magneto-dielectric (MD) materials have received much attention due to their applications in design of high-performance antenna and microwave components. Usually, their permittivity and permeability are key parameters in design of these components. Unfortunately, full characterization of these parameters faces challenge of measurement coupling between permittivity and permeability. To address this issue, an electric and magnetic isolated sensor based on a planar resonance structure is proposed and verified. Several shorting pins are used to separate the electric and magnetic regions, which effectively reduces the measurement coupling between permittivity and permeability. These shorting pins form a magnetic cavity pins (MCP) structure. The resonance structure is used for permittivity measurement, and the MCP structure is designed for measuring permeability with enhanced sensitivity. Moreover, to further improve the quality factor, a metal patch and two 50 Ω chip resistors are integrated on the microstrip line. To extract the imaginary part, the quality factor calculated from S21 will be used. By integrating these techniques, the sensor developed in this paper provides possibility of full characterization of MD materials with high sensitivity. Moreover, the magnetic cavity provides more space than the original design, allowing measurement in the Ultra-Wideband (UWB) range possible. Two sensors are designed and fabricated for validating the sensitivity and accuracy. Several materials with different permittivity and permeability are measured. The extracted measurement values show high agreement with the reference values. The permeability errors for real and imaginary parts are smaller than 3% and 4.5%, respectively. And the permittivity errors are smaller than 2.6% and 6.4%.

Small planar antenna array design using length and spacing through Matlab‐HFSS interfacing

SummaryThis study presents a novel method for reducing return loss and achieving lower side lobe levels in small planar antenna arrays (PAAs). Quantum particle swarm optimisation (QPSO) findings are utilised for antenna design modelling and performance assessment utilising the MATLAB‐based moment's code approach and MATLAB‐HFSS interface. The mutual coupling between antenna components is considered and computed using the method of moments (MoM). Changing the array elements' length and spacing will accomplish the abovementioned objectives. The Matlab‐based moments code calculates the antenna components' length and spacing, and the antennas' length and spacing are used to produce the radiation pattern via the Matlab‐HFSS interface. Four examples of small PAA designs are given to illustrate how well the applied methodology works. The method discussed in this paper is generic and can be employed in the future for different sizes of the array elements and the different antenna array structure designs.

Enhanced angle estimation in MIMO radar: Combine RD-MUSIC and SDP optimization

Multiple Input Multiple Output (MIMO) radars are increasingly employed. However, with a growing array of antenna components, the dimension of the sampling covariance matrix and the computational complexity of traditional Direction of Arrival (DOA) and Direction of Departure (DOD) estimation algorithms increase exponentially. In order to accurately and effectively identify and locate signal sources and to optimize the computational complexity, this paper presents an innovative approach for detecting target numbers based on a Semi-Definite Programming (SDP) problem, which generates efficient solutions even for higher dimensions. In addition, the SDP’s robustness is developed through shrinkage adaptation using Large Covariance Matrices (LCMs), which are crucial for angle estimation. Following the effective detection of a target, the tapering estimation is applied to the LCMs under the computationally efficient Reduced-Dimension Multiple Signal Classification (RD-MUSIC) algorithm, which is more accurate and less computationally intensive than 2D search algorithms. Simulation outcomes demonstrate that the efficacy of our proposed model achieves high success rates in target detection and enhanced precision in DOA and DOD estimations.

A miniaturized passive wireless patch antenna sensor for structural crack sensing

This paper presents a miniaturized patch antenna sensor for structural crack sensing, and the patch antenna sensor can be interrogated wirelessly. The proposed patch antenna sensor can detect the expansion of structural crack through relative movement between antenna components, and the relationships between the antenna resonant frequency and the crack width were studied. By using Rogers RO3010 laminate with high dielectric constant as the dielectric substrate of the antenna, the size of the proposed antenna sensor is significantly reduced, and higher sensing sensitivity is achieved. Furthermore, the wireless interrogation methods of the patch antenna sensor were also studied. The resonant frequency of the patch antenna sensor was wirelessly interrogated using linearly polarized wide-band antennas. Compared with the previous patch antenna sensor, the overall area of the proposed antenna sensor has been reduced to 33.4%, and the miniaturized patch antenna sensor shows a sensing sensitivity of 116.1 MHz/mm, which is 2.6 times higher than the previous patch antenna sensor. A series of simulations and experiments have demonstrated the feasibility of the proposed patch antenna sensor for structural crack sensing and the effectiveness of wireless interrogation methods.

Wideband high-gain low-profile series-fed antenna integrated with optimized metamaterials for 5G millimeter wave applications.

This paper presents a series-fed four-dipole antenna with a broad bandwidth, high gain, and compact size for 5G millimeter wave (mm-wave) applications. The single dipole antenna provides a maximum gain of 6.2 dBi within its operational bandwidth, which ranges from 25.2 to 32.8GHz. The proposed approach to enhance both gain and bandwidth involves a series-fed antenna design. It comprises four dipoles with varying lengths, and a truncated ground plane. These dipoles are connected in series on both sides, running in parallel through a microstrip line. The proposed design significantly enhances the bandwidth, which extends from 26.5 to 40GHz. This frequency range effectively covers the 5G bands of 28 and 38GHz. The expedited trust-region (TR) gradient-based search algorithm is utilized to optimize the dimensions of the antenna components, resulting in a maximum gain of 11.2 dBi at 38GHz. To further enhance the gain, modified H-shaped metamaterial (MTM)-based unit cells are integrated into the antenna substrate. The TR algorithm is employed once more to optimize the MTM dimensions, yielding a maximum gain of 15.1 dBi at 38GHz. The developed system is experimentally validated, showing excellent agreement between the simulated and measured data.

ENERGY EFFICIENT OPERATION FOR NEXT GENERATION MASSIVE MIMO NETWORK

For the next generation of wireless networks, massive multiple-input, multiple-output (MIMO) is regarded as a potential technique. Base stations (BS) are provided with a relatively large number of antenna components in massive MIMO in order to increase spectral efficiency (SE) and energy efficiency (EE). Meanwhile, EE of BSs are becoming an increasingly important concern for communications operators in order to maintain profitability and reduce the overall negative impact on the environment and economic concerns for wireless network users. In this paper, an energy-aware, load-adaptive operation approach is proposed for massive MIMO for the next generation of wireless communication systems. Energy-aware, load-adaptive network operation has been identified as a promising method for improving the energy efficiency of telecommunication networks. Our research indicates that at optimal sumSE, fully load-adaptive massive MIMO may greatly increase network EE by up to 8.666&amp;#37;, 43.317&amp;#37;, and 69.367&amp;#37; for high, medium, and low load factors, respectively, when compared to traditional non-load-adaptive massive MIMO.

Design of Rectangular Patch Microstrip Antenna with Defected Ground Structure Method at 3.5 GHz Frequency for 5G Technology

5G technology is currently developing rapidly in various countries. 5G technology has three sub-frequencies: low band, midband and high band. Midband frequencies in Indonesia are between 2.6 GHz and 3.5 GHz. In order for 5G technology is able to be used in Indonesia, it needs an antenna that can work at 3.5 GHz and has a wide bandwidth. Microstrip antenna is a simple and efficient antenna. However, microstrip antenna has minimal bandwidth. To overcome this, certain methods are needed, one of which is the defected ground structure (DGS) method. The initial design of the antenna has dimensions according to the results of the calculation formula. Then optimization is carried out by reducing the dimensions of the antenna components. After that, the DGS method is applied to widen the bandwidth. The initial design of the single-patch antenna before using the DGS method has a return loss value of -19.96 dB, VSWR 1.22, with a gain value of 3.812 dB and bandwidth 105.1 MHz. The simulation results of the antenna using DGS have a return loss value of -39.76 dB, VSWR of 1.02, with a gain value 3.16 dB and a bandwidth of 158.4 MHz. These results prove that the use of the DGS method can increase bandwidth.

A reconfigurable wideband MIMO antenna combines RF energy harvesting

SummaryThis article introduces a novel and groundbreaking approach combining multiple‐input‐multiple‐output (MIMO) technology with radio frequency (RF) energy harvesting. The proposed antenna consists of two semi‐circular monopole antenna components, optimized with dimensions of 89 × 51.02 × 1.6 mm3, that share a common ground plane to achieve MIMO characteristics. A series of split‐ring resonators on the ground plane significantly enhances the isolation between the two radiating components. Band‐notched features are performed in the 3.5 GHz WiMAX and 5.5 GHz WLAN bands through modified C‐shaped slots in the radiating patch and two rectangular split‐ring resonators serving as parasitic devices near the feed line. The reconfiguration of band‐notching is made possible by controlling the modes of the embedded PIN diodes. The two antenna elements maintain mutual coupling below −18 dB from 1.5–13 GHz, achieving an impressive 158.62% impedance bandwidth. The antenna's efficiency and gain experience significant drop, indicating effective interference suppression at the center frequencies of the notch bands, and its performance in MIMO systems is assessed through parameters including envelope correlation coefficient, port isolation, radiation patterns, efficiency, gain, and diversity gain. The simulated properties of the designed antenna closely align with the measured outcomes, demonstrating its reliability and consistency. Moreover, the article evaluates the antenna's potential for RF energy harvesting, achieving a maximum harvested energy of 4.88 V. This proposed antenna can be used in multiple applications, like wideband, band‐notching MIMO, and RF energy harvesting. This proposed antenna is an efficient, reconfigurable wideband MIMO antenna with novel RF energy harvesting capability.

Design and Performance Evaluation of Cavity-Backed SIW Antenna for Monopulse Applications

The design of a cavity-backed substrate integrated waveguide (SIW) dual-plane antenna for monopulse application is presented in this publication. The primary objective is to create a four-element circularly polarized cavity-backed slot antenna array that is compact and highly efficient. Two antenna subarrays are utilized to develop a complete analysis, design, and implementation of an antenna, and each antenna element can be used as an independent antenna for monopulse applications. The antenna element is made up of two square ring slot antenna components, a power divider, and a feed point. To produce sum and difference signals, the feed point of each antenna element can be connected to one of the input ports on a monopulse comparator. The antenna's performance at 10 GHz was assessed regarding radiation pattern, gain, return loss, bandwidth, axial ratio, and efficiency. A high-frequency structure simulator (HFSS) simulates a complete planar and compact SIW structure with a footprint of 61.6 mm x 58.1 mm. With a permittivity of 3.55 and a thickness of 1.524 mm, an antenna is manufactured using a photo-lithographic process on a single-layer Rogers RO4003 substrate. As per experimental findings, the antenna has a return loss of -40.17 dB, an RL bandwidth of 395 MHz, a gain of 13.11 dB, an axial ratio of 2.97 dB, and an efficiency of 89.85% at a frequency of 9.92 GHz. Experimental findings reveal exceptional performance parameters for the designed antenna, which can be used for monopulse applications at 10 GHz.

Suppression of axial vibration of satellite antennas using the self-resetting frictional damper

In order to solve the problems of low-profile accuracy and poor control stability of the satellite antenna due to axial coupling vibration, in this paper, a self-resetting friction damper is proposed to suppress axial vibration. Firstly, a self-resetting friction damper, with a lightweight, wide frequency band, and high energy consumption, is designed. The principle of dry friction energy loss of metal rubber (MR) and the effect of self-resetting of shape memory alloy (SMA) are used. Secondly, the vibration reduction mechanism model of the self-resetting friction damper is established, and the principle of damping energy dissipation is analysed. Finally, sinusoidal excitation tests of the components of the satellite antennas with self-resetting friction dampers are carried out. The axial vibration loss factor of the components of the satellite antenna with the self-resetting friction damper is calculated, and the vibration resistance performance of the damper is verified. Theoretical analysis and experimental results show that the self-resetting friction damper has a significant effect on suppressing the axial vibration of the components of the satellite antenna. It is feasible to install a self-resetting friction damper in the components of the satellite antenna to suppress the axial vibration.

A Bendable Wideband Dual-Polarization Conformal Phased-Array Antenna

In this letter, we proposed a bendable wideband dual-polarization low-profile conformal phased array antenna. The antenna element is an Invert-F fed stacked-patch antenna. It provides an active VSWR < 3 for 10.7 GHz to 12.75 GHz in the principal planes. The proposed phased array antenna employs a row modular architecture, which enables it to bend to a cylindrical geometry. Both the antenna aperture and the active components of the conformal phased array antenna are considered for bending in the letter. A prototype conformal phased array antenna with 8 rows of 4 dual-polarization antenna element was fabricated, assembled and measured. Wide-angle beam scanning is achieved by electronically scanning along the curved axis of the cylindrical conformal phased array antenna. Moreover, there is no grating lobe when scanning down to 60°.