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Advanced Electromagnetics
Journal Prestige (SJR): 0.154

Citation Impact (citeScore): 1
Number of Followers: 15

This is an Open Access Journal

Open Access journal
ISSN (Online) 2119-0275
Published by Advanced Electromagnetics

[1 journal]

Broadband Printed Slot Antenna Fed by CPW Loaded by Planar Artificial
Magnetic Conductor for X-Band Operation
- Authors: H. Malekpoor
  Abstract: A low profile printed slot antenna (PSA) backed by broadband planar artificial magnetic conductor (AMC) is introduced in this study. Firstly, a suggested PSA with the radiating tapered slots excited by coplanar-waveguide (CPW) is used to expand the bandwidth in the measured range of 9-11 GHz (S11≤ -10 dB). Then, the suggested planar AMC surface as the ground plane of the antenna is inserted into the PSA to gain improved radiation efficiency. The realized result from the PSA with the 9×9 planar AMC array exhibits -10 dB measured impedance bandwidth from 6.63 to 13.73 GHz (70%). The suggested PSA with AMC compared to the PSA without AMC exhibits a size reduction of 60%, enhanced bandwidth of 50%, and excellent impedance matching with a minimum value of almost -40 dB. The novel AMC unit cell is realized to operate at 10.14 GHz with an AMC bandwidth of 8-12.35 GHz (43.1%) for X-band operation. Besides, by loading a periodic AMC unit cells into PSA, a high gain of more than 11 dBi with uni-directional radiation patterns is achieved.
  PubDate: Tue, 24 Jan 2023 00:00:00 +010
Theoretical design and experimental study of magnetic circuit for
magnetorheological (MR) damper of shear-valve mode
- Authors: Y. Liu; A. Li, Z. Sun, S. Chen
  Abstract: According to the analysis of shear flow and pressure difference flow of MR fluids, the damping force of MR shear-valve damping force was analysed and calculated, and a magnetic circuit of Magnetorheological (MR) damper was designed. Based on the designed magnetic circuit, the degree of magnetic saturation and the dynamic characteristics of MR fluid damper, such as impedance, current, velocity and frequency were investigated. Magnetic induction testing of damping clearance was conducted, the test results show that when the coil current is 1.4A, the magnetic induction intensity reaches 0.55T.The bench test results show that when the piston speed is constant and the current is less than 1.36A, the variation range of damping force increases significantly. However, when the current is greater than 1.36A, the damping force tends to be stable and the coil reaches magnetic saturation, and energy indication characteristic of MR damper also show the same trend, which are consistent with the theoretical results. The results of this study can provide useful guidance for the magnetic circuit design of shear-valve MR fluid damper.
  PubDate: Sat, 31 Dec 2022 00:00:00 +010
A Low-profile 4-element Circularly Polarized Hexagonal DRA Array for
Triple-band Wireless Applications
- Authors: A. Vahora; K. Pandya
  Abstract: This paper presents a triple-band low-profile circularly polarized (CP) hexagonal dielectric resonator antenna (HDRA) array for various wireless applications. A 4-element linear array is designed using a simple microstrip power divider to improve the performance of the HDRA. This HDRA excites TEd01 mode at a first resonant frequency of 1.52 GHz. The proposed design operates in three frequency bands, i.e. 1.44 - 1.61 GHz, 2.95 - 3.27 GHz, and 4.00 - 4.84 GHz with the fractional bandwidth of 10.98%,
  11.02% and 22.20%, respectively. It also provides good gain and more than 70% of radiation efficiency with a better radiation pattern at all the resonating points. Further, it has a CP bandwidth of 50 MHz and 650 MHz around 3.12 GHz and 4.25 GHz, respectively. The proposed HDRA array is suitable for different wireless applications such as GPS (1 - 2 GHz), WiMAX (2 - 4 GHz), and WLAN (4 - 8 GHz).
  PubDate: Sat, 31 Dec 2022 00:00:00 +010
Parasitic Array Based Radiation Pattern Reconfigurable Patch Antenna for
WLAN Application
- Authors: B. Saikia; K. Borah
  Abstract: This article presents a radiation pattern reconfigurable patch antenna using three rectangular parasitic elements for WLAN (5.8 GHz) application. A rectangular driven patch with two parasitic elements placed parallel to both non-radiating edges and the third parasitic element is located on the radiating edge of driven element. The parasitic elements located on non-radiating edges are loaded with shorting posts. The electrical connection between the post and ground plane is controlled by an RF PIN diode switch. Based on switching state (ON/OFF) of the PIN diodes, post loaded parasitic elements, switch their function between director and reflector to produce beam reconfiguration in the proposed antenna. For different switching combinations of the PIN diodes, beam steering directions in H-plane are obtained at 0˚, +50˚, –50˚ for E-plane radiation maximum at +30˚, while fourth beam steering angle is found at ±50˚ with corresponding E-plane radiation maximum at ±40˚. Measured peak gain of the proposed antenna varies between 3.46 dBi and 3.74 dBi for different beam steering modes. With measured resonant frequency around 5.85 GHz throughout the reconfiguration process, the proposed antenna is considered as a potential candidate for WLAN application.
  PubDate: Sun, 30 Oct 2022 00:00:00 +020
The Performance Enhancement of Triple-band Vivaldi Antenna using SIW
Structure for IIoT applications
- Authors: T. D. Nguyen; T. T. T. Duong, D. D. Pham
  Abstract: The Industrial Internet of Things (IIoT) is a domain between IoT and Industry 4.0 that brings an evolution in automation and data exchange. Multiband and the wideband antenna are an important part to support high-rate IoT/IIoT communication through the wireless systems. In this study, we optimized a Vivaldi antenna for triple-band operation at well-known IIoT bands without adding any slot or extra structure. The antenna gets a large bandwidth of over 8%, 12%, and 19% at 2.4GHz, 4GHz, and 5.6GHz resonant frequencies, respectively. To improve several antenna characteristics such as resistance matching, gain, and radiation efficiency, an L shape symmetric Substrate Integrated Waveguide (SIW) structure is proposed. At the 5.6 GHz band, the SIW antenna achieves over 25% increase in radiation efficiency that reaches 99% although FR4 substrate is chosen to design the antenna. The proposed Vivaldi antenna is analyzed using CST simulation and measured using VNA equipment with an agree well result. Besides, we also set up a reality wireless system to test the antenna at two important IIoT bands: 2.4GHz and 5GHz.
  PubDate: Sun, 30 Oct 2022 00:00:00 +020
General Approaches to Solving Problems of Analysis and Synthesis of
Directional Properties of Antenna Arrays
- Authors: I. Islamov; E. Humbataliyev
  Abstract: The work carried out the calculation and synthesis of antenna arrays used in radio-electronic complexes on unmanned aerial vehicles. The analytical model is designed to find asymptotic estimates of the polarization components of the electric field of the grating in the far zone of the carrier surface; the results obtained with its use are the initial data for constructing a technique for the numerical solution of a boundary value problem for a grating on a carrier surface in the CST MWS electrodynamic simulation environment. The synthesis of gratings with the maximum achievable coefficient of directional action is carried out with the control of radiation patterns at a given set of angles. A two-mirror antenna system has been calculated. It is shown that with an increase in the number of re-reflections taken into account, the convergence of the result for the calculated characteristics of the antenna is observed. To test the proposed method, the same antenna was calculated using the integral equation method. The comparison showed a high degree of agreement between the results obtained by two different methods. The results of the simulation based on a software algorithm designed to quantify the input matching at the input of a multichannel frequency-scanning antenna array power divider are presented. It was found that when performing wide-angle scanning in a relative frequency band of more than a few percent, the disadvantage of the known method for eliminating the normal effect is a sharp deterioration in matching in the lower and upper frequencies of the operating range. A new method is proposed based on an automated iterative process of optimizing the divider geometry, which makes it possible to obtain an acceptable match over the entire operating frequency band. The feasibility of switching from a serial power divider construction scheme to a series-parallel scheme is analyzed for wide-angle scanning in a relative frequency band of about 5%.
  PubDate: Thu, 27 Oct 2022 00:00:00 +020
Influence of the orbital configuration of a four-rail electromagnetic
launcher on Joule heat
- Authors: P. Zhang; T. Shu
  Abstract: During the working process of electromagnetic launcher, the rapid temperature rise caused by heat accumulation has an important influence on the performance and life of the armature and rail. In order to better solve the thermal ablation problem of the armature and rail of the four-rail electromagnetic launcher, three different configurations of the rail and armature model are established, using the finite element method, the Joule heating characteristics of the three structures are simulated, analyzed and compared. The simulation results show that the Joule heat of the armatures of the three structures is concentrated at the throat, and the Joule heat of the rail is concentrated at the edge of the rail and the contact surface of the pivot rail; among the three structures, the electromagnetic launcher of the convex rail-concave armature structure has the smallest temperature rise rate, in addition, the peak temperature on the contact surface between the armature and the guide rail is the lowest, the safety of the ammunition is the highest, and the performance is more advantageous than the electromagnetic launcher of the other two structures.
  PubDate: Wed, 05 Oct 2022 00:00:00 +020
Microwave Scattering Characteristics of a Cylindrical Conductor Coated by
Dispersive Metamaterials with an Intervening Air Gap
- Authors: A. G. Jamil; T. C. K. Rao
  Abstract: Plane wave scattering characteristics of a conducting cylinder coated by a layer of metamaterial (MTM) having dispersive and lossy constitutive parameters – permittivity (ε) and permeability (μ) - with an intervening air gap is investigated by using the boundary-value technique. The backscattering cross section (BSCS) or the monostatic radar cross section (RCS) has been obtained for both the TM and the TE incident wave polarizations. Analysis based on a mathematical model, namely the Drude-Lorentz dispersion model, for the MTM coating shows that for a certain range of frequencies, the material may behave as either permeability- (or mu-) negative (MNG), permittivity- (or epsilon-) negative (ENG), both- (or double-) negative (DNG) or finally as both- (or double-) positive (DPS). The dispersive and lossy characteristics of these materials combined with the added features of an air gap (which can be practically realized by a layer of Styrofoam) seem to indicate that it is possible to achieve an extremely low radar echo width over a broad range of frequencies, particularly for the DNG type MTM. Further investigations on the total scattering cross section (TSCS) for the DNG type MTM, appear to demonstrate that near perfect broadband cloaking is possible with this geometry.
  PubDate: Tue, 20 Sep 2022 00:00:00 +020
Generation of double-exponential EMC pulses with Software-Defined Radios
- Authors: M. B. Perotoni; M. S. Vieira, K. M. Santos
  Abstract: This article presents a system to generate transient signals for EMC testing purposes. It is based on a low-cost commercial Software-Defined Radio (SDR) whose output contains the desired transient signal modulated by a higher-frequency sinusoidal. An envelope detector board removes the carrier so that the slow-varying curve is amplified to be used in the test setup. Due to the SDR nature, it is completely controlled by software, which enables a quick and easy operation able to synthesize different waveforms. An open-source software tool is used to control the SDR to generate the signal and set the carrier frequency. Here, the article focuses on double-exponential curves, very common in different EMC tests, but its application is not limited to them. A 5.9 s risetime waveform is generated and tested against a real prototype representing a shielded cable over a ground plane. Individual building blocks are presented and the signal is analyzed as it goes through the cascade.
  PubDate: Tue, 20 Sep 2022 00:00:00 +020
A Compact Circular Polarized MIMO Fabric Antenna with AMC Backing for WBAN
Applications
- Authors: T. U. Pathan; B. Kakde
  Abstract: A compact high-isolation diversity and circular polarized (CP) multiple-input multiple-output (MIMO) fabric antenna for 2.4 GHz ISM band applications is presented. A metamaterial (MTM)-inspired radiating element is used for the miniaturization of the presented fabric antenna. The proposed antenna is fabricated on a denim substrate and has a dimension of 58 mm x 23 mm x 1.6 mm. The circular polarization is achieved by trimming the two diagonal corners of the radiating elements. A defected ground structure (DGS) comprising two U-slots is placed underneath each radiator to increase the bandwidth of the presented antenna. The isolation characteristics between the two antenna elements are increased by 20 dB by cutting a slit in a ground plane. The proposed CP-MIMO antenna incorporates an artificial magnetic conductor (AMC) layer to limit backward radiation towards the human body and hence enhances the gain. This antenna has been created on a denim substrate with permittivity εr =1.6 and 1.6 mm thickness. The proposed antenna offers a fractional bandwidth of 6.6 % (2.38-2.54 GHz), and an impedance bandwidth about 160 MHz. The antenna has a peak gain of 2.5 dBi without AMC and 4.5 dBi with AMC. To validate the simulation results, a prototype for the proposed antenna has been fabricated and experimentally characterized. Due to its small size, low specific absorption rate (SAR), ease of integration, and robustness, this antenna is a good option for wireless body area network (WBAN) applications.
  PubDate: Mon, 08 Aug 2022 00:00:00 +020