| Publisher: Advanced Electromagnetics
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Advanced Electromagnetics
Journal Prestige (SJR): 0.154  Citation Impact (citeScore): 1 Number of Followers: 16  Open Access journalISSN (Online) 2119-0275 Published by Advanced Electromagnetics  [1 journal]
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- Electrothermal Analyses of Bandpass NGD RLC-Network Topologies
Authors: E. J. R. Sambatra; S. Ngoho, F. Haddad, M. Guerin, G. Fontgalland, W. Rahajandraibe, B. Ravelo
Abstract: This paper develops an original study of temperature effect on the unfamiliar bandpass (BP) negative group delay (NGD) lumped passive circuits. The paper presents the first study of electrothermal analysis of electronic circuits classified as BP-NGD topologies. The considered BP-NGD passive cells are mainly constituted by RLC-resonant networks. The equivalence between two basic BP-NGD topologies constituted by RLC-series and RLC-parallel networks is elaborated via the voltage transfer function (VTF) analogy. Then, the theoretical demonstrations are introduced to define the main specifications as the NGD center frequency, NGD value, attenuation and NGD bandwidth. The electrothermal innovative study is developed based on the temperature coefficient resistor (TCR) of elements constituting the BP-NGD circuits. With proofs of concept of RLC-series and RLC-parallel circuits operating with -500 ns NGD value at 13.56 MHz, calculated and simulated results showing are in excellent agreement. The sensitivity analyses of BP-NGD specifications in function of ambient temperature variation from 0°C to 100°C are investigated. The BP-NGD response variations versus frequency and temperature are characterized with thermo-frequency cartographies and discussed.
PubDate: Sat, 11 Mar 2023 00:00:00 +010
- Design of Wide-Band Microstrip Antenna for S-Band Telemetry Applications
Authors: Pushpalatha M; Namana N, T. S. Navadagi, Varun D
Abstract: This paper exemplifies the design of a low profile wide-band microstrip antenna suitable for S-Band telemetry applications. The proposed design explores the concept of wide-band antenna with improved omnidirectional gain and smaller size essentially aiming at low-earth orbit (LEO) satellite telemetry. The proposed partial annular radiating patch design has an operating impedance bandwidth ranging from 2.7 GHz to 3.8 GHz with a percentage bandwidth of 31%. It exhibits vertical polarization with a gain of around 1.434 dBi. The design and simulations are carried out using 3D EM tools and the measurement results for various performance metrics of the antenna are validated with the simulation results.
PubDate: Sat, 11 Mar 2023 00:00:00 +010
- Electromagnetic guided mode resonance in dielectric grating affected by
transformation of refractive index periodicity
Authors: A. Abramov; Y. Yue, V. Rumyantsev
Abstract: The present work studied effects of transformation of refractive index periodicity on electromagnetic wave propagation through grating waveguides. In lieu of the standard refractive index periodicity, although its unit cell consists of two kinds of materials, we consider few such unit cells as a new supercell, where the material parameters in a standard unit cell are changed. It has been shown how by changing parameters of the periodicity to control the wavelength and intensity of resonant optical mode (guided mode resonance) arising inside grating area. High quality factor calculated for the specific angle of incidence and periodicity parameter. Thus, we demonstrated that transformation of refractive index provides additional tools of controlling the GMR, and that means the sample can be designed more functional in terms of real application.
PubDate: Sun, 12 Feb 2023 00:00:00 +010
- On the Computation of the Attenuation Constant by Using the Generalized
Telegraphist’s Equations Based Electromagnetic Analysis Method
Authors: S. Simion
Abstract: Numerical results for the attenuation constant obtained by using the generalized telegraphist’s equations (GTEs) based electromagnetic analysis method and comparison with the HFSS (High Frequency Structure Simulator) results are reported. To calculate the attenuation constant with the GTEs method, not only the amplitudes of the voltage modes but also the amplitudes of the current modes must be found. In this paper, it is demonstrated that the relationships reported by other authors for the amplitudes of the current modes are not correct and new ones are proposed. To validate these relationships, the attenuation constants for homogeneous and different partially dielectric-filled rectangular waveguides are computed for the fundamental propagation mode by using the GTEs based analysis method and the results are compared with those obtained with HFSS. It is shown that using the revised relationships for the amplitudes of the current modes, the GTE method can be used to compute accurately the propagation and attenuation constant, but only for propagation modes in which the components of the electric field are not oriented perpendicular to the interface between different dielectrics. This limitation is not due to the proposed current mode relationships, but is due to the GTE method which cannot highlight the electric field discontinuities.
PubDate: Sun, 12 Feb 2023 00:00:00 +010
- 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
