Wave Radiation Pattern Research Articles

Gain enhancement of compact CPW‐Fed ultra‐wideband antenna using an FSS reflector

AbstractIn this paper, an enhancement gain of compact CPW‐Fed antenna using a single layer frequency selective surfaces (FSSs) reflector for ultra‐wideband (UWB) applications is presented. A hexagonal CPW‐Fed antenna with a size of 30 × 30 mm2 is realized to provide a UWB bandwidth operation. In this study, a novel design of an FSS unit cell with reduction and a small size of 8 × 8 mm2 is proposed. It allows one to achieve a UWB band‐stop response between 3 and 11.5 GHz. The FSS reflector has 7 × 7 units with a total size of 56 × 56 mm2. This reflector is placed below the antenna at a distance of 20 mm. The main objective of this contribution is to improve the gain level of the antenna, where the proposed antenna achieves an improvement of realized gain of 6.2 dBi with increasing from 2.2 to 8.4 dBi. The antenna became more directive after the integration of the FSS reflector with a directional radiation pattern. The numerical and experimental results are in good concordance with the simulated one. This study is performed in terms of voltage standing wave ratio, radiation pattern, realized gain, and radiation efficiency.

Design and analysis of a microstrip antenna for superior 5G communication performance

The continuous advancement in communication systems is propelled by the growing demand for fifth-generation (5G) technology, aiming to meet the growing demands of systems that are small in size, operate at high speeds, and have a wide bandwidth. In order to address these requirements, innovative and highly efficient antenna configurations are of paramount importance. This article introduces a microstrip antenna that has been meticulously designed for optimal performance 5G systems. Optimized for 5G communication systems, the research focuses on the design and simulation of microstrip patch antennas which is shaped like butterfly, resonating at a frequency of 50.5 GHz. A Rogers RT5880 (lossy) substrate with a dielectric constant of 2.2 was employed in the antenna design. The dimensions of the proposed antennas were 6 × 6.5 × 0.787 mm³, which resulted in a geometric configuration resembling a butterfly. A comprehensive performance assessment involves exhaustive simulations using the CST Studio Suite application suite. In order to optimize critical parameters such as the Voltage Standing Wave Ratio (VSWR), reflected power, gain, frequency range (BW), and radiation pattern, the dimensions were meticulously adjusted. Significantly, the antenna operating at 50.5 GHz demonstrated a gain of 6.8 dB, in addition to a broad bandwidth of 5.364 GHz and an outstanding VSWR of 1.0131. The outcomes successfully underscore the outstanding performance exhibited by the butterfly-shaped design, thereby establishing its suitability for implementation in 5G networks.

A hybrid energy supply system based on metamaterial antenna integrated solar cells for IoT nodes

In this paper, a hybrid energy supply system based on solar cells integrated metamaterial (MTM) antenna is presented for use in Internet of Things (IoT) nodes. The work develops an energy supply system having dimensions of 40×40 mm2, that is qualified for storing and releasing energy. To realize miniaturization technique and gain enhancing, the design of antenna employs complementary split-ring resonator (CSRR) and a 4×1 array. Meanwhile, this work is miniaturized by integrating solar cells on the substrate. The result is a very compact integrated antenna with overall dimensions of 82.5×33 mm2 and the ability to harvest radio frequency (RF) energy and solar energy, which covers frequency band from 5.2 to 6.2 GHz. Different antenna structures were built to analyze S11 spectra, voltage standing wave ratio (VSWR), radiation patterns and surface current distribution, respectively. For further verification, the design was fabricated and compared to the simulated one. Moreover, practical experiments were conducted with four kinds of environment setup. The fabricated antenna provides maximum voltage of 1.63 V, indicating a good applicability to RF energy harvesting. The energy supply system provides a stable output voltage with 2.9 V in different conditions. The results highlight the feasibility of energy supply system in energy harvesting and powering for various IoT nodes.

Design and analysis of frequency reconfigurable antenna in S-band

One of the biggest challenges in modern communication systems is to provide a single antenna for multiple applications. Existing antenna systems are limited to some applications. Therefore, it is important to design a single reconfigurable antenna for multiple applications in current communication systems. To overcome this problem, a single antenna with frequency reconfiguration capability has been developed in this work. In this work, four different frequency reconfigurable antenna layouts are investigated. To provide frequency reconfigurability, the proposed antenna comprises two P-intrinsic-N (PIN) diodes placed between the microstrip line and patch. The antenna can resonate in four states and operate at three distinct frequencies without affecting the size of the antenna by toggling the 'ON' and 'OFF' modes of the PIN diodes. The antenna can operate at three different frequency ranges, depending on the switching state of the PIN diode 2.1, 2.4 and 3.0 GHz. The voltage standing wave ratio (VSWR), gain, return loss (RL) and radiation patterns of the antennas were simulated and measured. It is clear that the proposed antenna works at different operating frequencies. The gain and RL for the corresponding frequencies are significantly improved and the radiation pattern is symmetrical.

Elastic wave radiation and reception of a borehole dipole source in a vertically transverse isotropic formation

Single-well acoustic imaging using a dipole tool has been applied in anisotropic formations. For this application, the effect of anisotropy on the radiation and reception of acoustic waves in the borehole needs to be analyzed and a proper analysis method needs to be developed. We use the far-field asymptotic solution of the wavefield to calculate the radiation pattern of the dipole source in a borehole penetrating vertically transverse isotropic (VTI) formation. We model the spherical wave propagation characteristics of the radiated and reflected waves in the VTI formation and the receiving of the waves in the borehole for the on- and off-axis positions. Based on the developed analytical modeling methods, we study systematically the effects of the formation anisotropy on the radiation pattern and borehole response characteristics. Our modeling result demonstrates that due to the coupling between the longitudinal and the transverse particle motions, quasi-P-(qP-) and quasi-SV-(qSV-) wave radiation patterns contain two components. The result also indicates that the anisotropy causes the arrival time of the SH-reflection wave to differ from that of the qSV wave, and the misposition of the imaged targets would occur if the velocity measured along the borehole is used for migration. The azimuth sensitivity of the off-axis data can be used to help eliminate the 180° ambiguity for the dipole acoustic imaging in the VTI formation. Understanding the effects of anisotropy on borehole acoustic imaging can help improve the accuracy of the imaging result in anisotropic formations.

Defected Ground Structure Multiple Input-Output Antenna For Wireless Applications

In this paper, the investigation of a novel compact 2 × 2, 2 × 1, and 1 × 1 Ultra-Wide Band (UWB) based Multiple-Input Multiple-Output (MIMO) antenna with Defected Ground Structure (DGS) is employed. The proposed Electromagnetic Radiation Structures (ERS) is composed of multiple radiating elements. These MIMO antennas are designed and analyzed with and without DGS. The feeding is introduced by a microstrip-fed line to significantly moderate the radiating structure’s overall size, which is 60 × 40 × 1 mm. The high directivity and divergence characteristics are attained by introducing the microstrip-fed lines perpendicular to each other. And the projected MIMO antenna structures are compared with others by using parameters like Return Loss (RL), Voltage Standing Wave Ratio (VSWR), Radiation Pattern (RP), radiation efficiency, and directivity. The same MIMO set-up is redesigned with DGS, and the resultant parameters are compared. Finally, the Multiple Input and Multiple Output Radiating Structures with and without DGS are compared for result considerations like RL, VSWR, RP, radiation efficiency, and directivity. This projected antenna displays an omnidirectional RP with moderate gain, which is highly recommended for human healthcare applications. By introducing the defected ground structure in bottom layer the lower cut-off frequencies of 2.3, 4.5 and 6.0 GHz are achieved with few biological effects on radio propagation in human body communications. The proposed design covers numerous well-known wireless standards, along with dual-function DGS slots, and it can be easily integrated into Wireless Body Area Networks (WBAN) in medical applications. This WBAN links the autonomous nodes that may be situated either in the clothes, on-body or beneath the skin of a person. This system typically advances the complete human body and the inter-connected nodes through a wireless communication channel.

Dual wide band patch antenna for WLAN/WiMAX and X-Band operations

A compact, wideband microstrip antenna with dual-band characteristics is modelled on FR-4 (εr = 4.4, tanδ = 0.02) with an overall measurements of 20 mm × 20 mm × 1.6 mm. The antenna structure engages at 5 GHz with a 10-dB bandwidth of 3160 MHz (63.2 % fractional bandwidth at 5 GHz center frequency) and at 9.3 GHz with a 10-dB bandwidth of 1900 MHz (20.44 % fractional bandwidth at 9.3 GHz center frequency). The return loss observed is −44.6 dB at 5 GHz and −49.1 dB at 9.3 GHz. The practical specifications such as return losses, current distributions, bandwidths, voltage standing wave ratio and radiation patterns are investigated by utilizing the Ansys HFSS 2020 R2 simulation tool and has presented in the results. Thus the addressed antenna is appropriate for the WLAN, WiMAX and X-band operations.

DESIGN AND DEVELOPMENT OF SUPER WIDEBAND DIELECTRIC RESONATOR ANTENNA FOR NEXT-GENERATION TELECOMMUNICATIONS

The dielectric resonator antenna (DRA) has revolutionized the latest generation of communication systems with their obvious advantages of small size, bandwidth, and power-consuming capabilities. In this paper, an analysis of the impact of the dielectric material on the radiation characteristics of the DRA is presented with simulation reports. The proposed antenna takes the shape of a circular patch with the dielectric resonator having different shapes. This helps to analyze the impact of the tapering adjustments on the features of the antenna. The simulations are performed using the latest version of the complex electromagnetic modeling tool, and results are analyzed in terms of simulated reports like reflection coefficient (S11), voltage standing wave ratio, radiation patterns, and field distribution plots. The overall size of the proposed antenna is 18 × 12 mm<sup>2</sup>. The measured results are in good agreement with the simulation results. The proposed DRA is suitable for mobile wireless applications.

Design and Simulation of Rectangular Microstrip Patch Antennas (45 GHz and 60 GHz) for V-band Applications

In this article, two wideband microstrip rectangular patch antennas have been designed and simulated for V band communication systems at resonant frequencies 45 GHz and 60 GHz. Rogers RO4730G3 is used as substrate dielectric with dielectric constant 2.98. The dimensions of the antennas are 6.23mm*6.7mm*0.7mm and 6mm*6.4mm*0.7mm respectively, with very simple geometrical configuration. To investigate the performance, the designs were then simulated using (CST) Studio Suite software package. The dimensions have been well studied and optimized to obtain acceptable results of Voltage Standing Wave Ration (VSWR), return loss, gain, bandwidth (BW) and radiation pattern. The 45 GHz antenna provides a gain of 6.73 dBi with the BW of 5.5 GHz and 1.03 of VSWR. Meanwhile, the 60 GHz design offers 6.92 dBi of gain with BW of 11.57 GHz and 1.05 of VSWR. The achieved results illustrate that both designs provide a good performance and are applicable for future 5G communication systems or any applications in the V band region.

Tightly Coupled Ultra-Wideband Phased-Array Implemented by Three-Dimensional Inkjet Printing Technique

In order to enhance the gains from antennas suitable for airplane-mounted platforms, a tightly coupled antenna array is investigated in this paper. Specifically, a three-dimensional (3-D) inkjet printing technique is used to implement the conformal characteristics needed for the array. Both the radiators and substrate of the antenna array have been fabricated by combining the fused deposition modeling and microdroplet injection molding technologies, based on an existing 3-D printer. Here, through a unique combination of 3-D and 2-D inkjet printing of dielectric material and metallic ink, respectively, we demonstrate a monolithically integrated design for a nonplanar antenna for the first time. The antenna measurements herein show the complete characterization of this new process in terms of minimum feature size and achievable conductivities. This antenna configuration offers a high-gain performance with a low-cost and rapid fabrication technique by using 3-D printing techniques. To check our design, the voltage standing wave ratio and radiation patterns were tested after adding the newly designed feed structure. The results show that the design process is very efficient. Both the antenna element and the array demonstrate positive properties and are in very good agreement with the specially mounted platform.

Design Analysis of 5G Microstrip Antenna

5G communication network has three distinct characteristics, although not limited to; enhanced network coverage, low latency and massive device connectivity. 5G mobile system has broad spectrum to support high data rates. Such device must deploy corresponding radiating structures to meet the changing technological advancement. In this paper therefore, a microstrip patch antenna operating at 3.6GHz frequency is designed and simulated for 5G application. The choice of frequency of operation is influenced by the broad prospects for 5G. The substrate is the flame resistant four (FR4) with a dielectric constant of 4.6 and a loss tangent of 0.023. The results include; plots of the voltage standing wave ratio, radiation pattern, return loss and radiation efficiency. The result further showed that, the parameters influencing the radiation characteristics of the patch antenna are the relative permittivity of the dielectric material, the position of the slot on the patch, the ground plane, substrate type as well as the dimensions of the feed and patch. The microstrip antenna thus can be effectively deployed for 5G application.

Optimum sensor configuration of surface arrays for retrieving accurate source mechanisms of microseismic events

Hydraulic fracturing and induced networks are significant for effective production of oil and gas from unconventional resources. The knowledge of fracturing source mechanisms is helpful for optimizing hydraulic fracturing treatments to maximize production. For source monitoring, the moment tensor inversion is commonly used and the source mechanisms are interpreted by the radiation patterns of microseismic waves. The accuracy of source interpretation is significantly influenced by sensor configurations, which still need further researches. In this study, the mechanism of sensor arrangements to suppress noise effect is analyzed and clarified mathematically, then an optimization method of searching for proper sensor configurations is proposed. For superior sensor configurations, errors caused by noise can be allocated evenly to the 6 moment tensor components and the source interpretation based on the moment tensor decomposition is till accurate, but errors can not be completely eliminated by optimizing sensor configurations. Generally, high-precision inversion results can be calculated by the sensor configuration that one sensor is at the center and the others are around at the same angular intervals. Compared with tradition sensor configurations, this new one can achieve similar inversion accuracy by less than a third of the sensors. Sensor numbers are not the more the better and dependent on the sizes of the regions of sensor arrangement. The conclusions arrived in this study are helpful for evaluating and designing sensor configurations for hydraulic fracturing monitoring.

Numerical investigation of near and far field ultrasound transducer radiation characteristics in concrete

Concrete is the most frequently used material in civil engineering. Therefore, it also plays an im-portant role for nondestructive testing methods like ultrasonic testing. In the past Dry Point Contact transducers have proven to be very efficient transmitters and receivers for ultrasonic testing of concrete. The individual element consists of a spring-loaded ceramic tip, driven by a piezoelectric bimorph and oscillating either normally or laterally with respect to the component surface. In order to predict the resulting sound fields quantitatively, appropriate modeling is required. Analytic formulas for the wave fields derived from elastic wave theory are available, however, they usually only cover bulk waves (body waves) in the far field and discrepancies between calculated and measured di-rectivity patterns are reported in the literature. We therefore conduct numerical simulations using the staggered-grid finite difference code EFIT to investigate radiation patterns of US transducers cover-ing surface and bulk waves in the near and the far field. The simulations are performed in a strongly heterogeneous, two-phased medium representing the material parameters and the mesostructure of concrete. With this model, the effects of damping as well as scattering at pores and aggregates on radiation characteristics shall be investigated in future. In order to validate EFIT results, measure-ments were conducted on a concrete specimen with an embedded tube as a test feature. As will be shown, a good agreement between measurements and simulations was found. During the evaluation of the simulation and measurement results focus was put on surface waves because a significant part of the wave field’s energy goes into the surface modes. Ultimately, these studies might be used for US transducer sensitivity analysis as well as for US testing reliability assessments in the future.

Rancang Bangun Antena Mikrostrip MIMO 4 Elemen Untuk Komunikasi 5G Pada Frekuensi Band N40

This study discusses the design of the MIMO microstrip antenna which is implemented in a 5G communication system that works on the N40 frequency band (2.3-2.4 GHz) with the center frequency of 2.35 GHz. The parameters that are unique of this antenna is focusing on the mutual coupling and correlation of MIMO antennas. The MIMO configuration was chosen because it can meet the high data transmission needs of 5G communication systems. The antenna is composed of a square patch with a microstrip insert feed-line technique. Then, the substrate uses FR-4 material, with a dielectric constant value of 4.3. After the design of a single element antenna that works according to the criteria is obtained, then the antenna is arranged into a configuration of 4 parallel elements, a 2×2 MIMO configuration with uniform polarization, and a 2×2 MIMO configuration with non-uniform polarization. After the design process, the antenna design is fabricated and then measured using a Vector Network Analyzer (VNA). The analysed antenna parameters are return loss, mutual coupling, Voltage Standing Wave Ratio (VSWR), bandwidth, and radiation pattern. From the element measurement results, it is found that the return loss is -11.24 dB and the bandwidth is 70 MHz at the center frequency of 2.35 GHz. As for the analysis of mutual coupling between elements, the best results were obtained from the MIMO configuration of 2×2 non-uniform polarization with values -20 dB for all elements. The antenna measurement results obtained indicate a similarity with the simulation results. This result is suitable for MIMO applications that require very low mutual coupling and correlation between elements.

Seismic Sources in Stress‐Induced Anisotropic Media

Rocks in the upper mantle are extensively subjected to initial stress. The rock exhibits elastic anisotropy under the deviatoric stress, which affects the seismic response of underground structures. This paper aims to study the effect of stress-induced anisotropy on the seismic source. The seismic moment tensor generated by a shear faulting in a homogeneous isotropic medium with initial stress is derived by using the motion description in the intermediate configuration, the constitutive relation of third-order elasticity, and the boundary condition considering the effect of initial stress. Then the seismic moment tensor is decomposed to investigate seismic source characters quantitatively. Our results show that shear faulting in a stress-induced anisotropic medium can produce significant non-double-couple (non-DC) mechanisms, including compensated linear vector dipole (CLVD) and isotropic (ISO) components. ISO and CLVD components vary linearly with the initial shear stress on faults. In addition, stress-induced anisotropy causes the double-couple (DC) to deviate from the plane defined by the fault normal and slip direction. The initial stress not only affects the source intensity but also affects the propagation of seismic waves. The radiation patterns of longitudinal waves have non-uniform lobes, which shows the characteristic of anisotropy. Stress-induced anisotropic parameters are smaller than intrinsic anisotropy at high-stress levels and a nearly linear function of the increased initial stress. These results underscore the importance of considering stress-induced anisotropy in the inversion of focal mechanisms and provide a new perspective for monitoring underground stress.

Design and Analysis of Microstrip Patch Antennas for Narrow Band Communication Applications

Abstract- Microstrip antennas are low-profile antennas. A metal patch mounted at a ground level with a dielectric material in between constitutes a Microstrip or Patch Antenna. These are very low- size antennas having low radiation. The patch antennas are popular for low-profile applications at frequencies above 100 MHz, these antennas consist of a very thin metallic strip placed on a ground plane with a dielectric material in-between. Usually, the antennas are chosen to be circular or rectangular in shape for ease of analysis and fabrication. These antennas are employed at ultra-high frequencies and higher frequencies. This paper aims to design and analysis of microstrip patch antennas for Narrowband Communication Applications by the analysis on antenna parameters such as Voltage Standing Wave Ratio (VSWR), S11 Parameters, Radiation Pattern and Gain. Dielectric materials FR4 Epoxy, RT Duroid 5880, RT Duroid 6006 and RT Duroid 6010 are considered whose permittivity is 4.4, 2.2, 6.15 and 10.2. The antennas are simulated at 900 MHz frequency using Ansys Electromagnetic Suite (HFSS) software and the resultant graphical analyses of the parameters are plotted. The antennas are also fabricated with the above dielectric materials and are tested for practical values using a network analyser using Midas software. The results show that RT-Duriod 6006 gives better values when compared to the other substrate materials. The gain observed is 12.6 dB with a VSWR of 1.65. From the obtained results, it can be concluded that the antenna made from this substrate material (RT-Duriod 6006) are best suited for narrow band communication applications.

Microstrip Patch Antenna

Abstract: Performance parameters like return loss, voltage standing wave ratio, gain, and radiation pattern are calculated. Design frequency is 2.4 GHz, the copper-coated substrate material is RT Duroid 5880 having dielectric constant ε=2.2 and thickness is 1.6 mm. The feeding technique, employed in Microstrip patch Antenna is Microstrip 50 Ω feed line. employing a parametric study found that the proposed antenna design are useful for ISM band applications like Wi-Fi, Bluetooth, 2G/3G/LTE mobile communication systems.

Use of 3D Printing for Horn Antenna Manufacturing

This article describes the manufacturing of a horn antenna using a 3D commercial printer. The horn antenna was chosen for its simplicity and practical versatility. The standardised horn antenna is one of the most widely used antennas in microwave technology. A standardised horn antenna can be connected to standardised waveguides. The horn antenna has been selected so that this antenna can be fabricated by 3D printing and thus obtain the equivalent of a standardised horn antenna. This 3D horn antenna can then be excited by a standardised waveguide. The 3Dprinted horn antenna with metallic layers has very good impedance characteristics, standing wave ratio and radiation patterns that are close to those of a standardised horn antenna. The 3D-based horn antenna is suitable for applications where low antenna weight is required, such as aerospace and satellite technologies. The article also describes a manufacturing procedure for a horn antenna (E-sector horn antenna) that is plated with galvanic layers of silver and gold. The design of the plated horn antenna in the Matlab application using the Antenna Toolbox extension is also described, including 3D printing procedures, post-processing procedures (plating) and practical testing of its functionality. The measured results are compared to simulations of the standardised horn antenna and then analysed.

Multi-input multi-output antenna measurements with super wide bandwidth for wireless applications using isolated T stub and defected ground structure

The paper presents the idea of defective ground structures for the improvement in the radiation characteristics of the antenna especially in the multi-input multi-output (MIMO) configuration. The proposed antenna model with partially flared out feed system is designed and analyzed with defective ground in both single and array configuration. A T stub is a T shaped stub used in this work with defected ground structure. A T stub is included along with defective ground to enhance the MIMO configuration features. The simulations are carried out on electromagnetic modelling tool and analyzed by measuring the parameters like reflection coefficient, voltage standing wave ratio (VSWR), gain, radiation pattern and current distribution plots. For the fabrication of the proposed antenna these measurements are very important. The antenna is fabricated and validated in terms of S-parameters and VSWR. The proposed results are good agreement with the simulated results. The overall size of the antenna is 24 × 18 x 0.8 mm<sup>3</sup>.

Research on HF antenna blockage effects and their alleviation

In this paper, blockage effects on high-frequency antennas are studied and their influence on the voltage standing wave ratio, gain, and radiation patterns is analysed. By simulating different blockage effects, the relationship between the antenna and the size of the blockage is clarified. It finds that radiation patterns are usually affected more seriously than other coefficients. The impact on the pattern is greater if the size or height of the blockage is larger than half of the wavelength. Two methods relating to the modification of the angle and height of the antenna are proposed that can reduce the influence of blockage effects. These are verified using a simulation and one is further demonstrated using a practical application.