Article
Mathematics, Interdisciplinary Applications
Stavroula Kapoulea, Costas Psychalinos, Ahmed S. Elwakil
Summary: This work presents a simple and direct approach for implementing fractional-order filters with transfer functions containing Laplace operators of different fractional orders. By considering the general fractional-order transfer function as a whole and approximating it using a curve-fitting-based technique, the main advantage is a significant reduction in the order of the resulting rational function compared to conventional procedures. Experimental results obtained using a field-programmable analog array device confirm the validity of this concept.
FRACTAL AND FRACTIONAL
(2021)
Article
Computer Science, Hardware & Architecture
Stavroula Kapoulea, Costas Psychalinos, Ahmed S. Elwakil, S. Hassan HosseinNia
Summary: This work introduces a novel procedure for the realization of a fractional-order PID loop-shaping controller suitable for precision control of mechatronic systems. The controller function is approximated as a whole, leading to a simple form of integer-order approximation for direct implementation and efficient functionality. Simulation and experimental results confirm the effectiveness of this implementation procedure.
INTEGRATION-THE VLSI JOURNAL
(2021)
Article
Engineering, Electrical & Electronic
Stavroula Kapoulea, Costas Psychalinos, Ahmed S. Elwakil
Summary: A new category of fractional-order fillers is introduced in this work, which can be achieved through an efficient curve fitting method to approximate the frequency-domain behavior of the filter and transpose the fractional-order transfer function into the integer-order domain. The designed filters do not require fractional-order elements for implementation, as they can be realized using conventional integer-order techniques.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2021)
Article
Computer Science, Information Systems
Stavroula Kapoulea, Costas Psychalinos, Ahmed S. Elwakil
Summary: A structure suitable for implementing power-law low-pass and high-pass filter transfer functions is proposed in this work. The full programmability of the characteristics of the intermediate stages is achieved through the utilization of a field-programmable analog array device, making the structure versatile. A comparison between power-law and fractional-order filters regarding the effect of the non-integer order is also performed.
Article
Chemistry, Multidisciplinary
David Kubanek, Jaroslav Koton, Jan Dvorak, Norbert Herencsar, Roman Sotner
Summary: This paper presents a detailed analysis of an operational transconductance amplifier based gyrator implementing a fractional-order inductance simulator. The influence of active element non-ideal properties on the gyrator operation is investigated, and recommendations to optimize the performance of the gyrator are proposed. The theoretical observations are verified through PSpice simulations.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Julia Nako, Costas Psychalinos, Ahmed S. Elwakil
Summary: In this work, a systematic method for approximating the complex-order Laplacian operator by realizable integer-order transfer functions is presented. The realization is achieved through a simple structure using only one active element. By employing complex-order impedances, both integrators and differentiators can be implemented interchangeably with the same core. The validity of the proposed concept is verified through simulation and experimental results using the OrCAD PSpice suite and a Field Programmable Analog array device.
INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Jingyu Zhang, Liangzong He, Zhile Lin
Summary: This article proposes a second harmonic current suppression method based on fractional-order capacitor (FOC), which does not require power supply and incurs little loss. The proposed method can achieve SHC suppression with the advantages of a simple control strategy, hot-swappable, and high flexibility. Most importantly, it can effectively suppress the first-order harmonic current caused by the asymmetrical parameters of the capacitors.
IEEE TRANSACTIONS ON POWER ELECTRONICS
(2023)
Review
Computer Science, Information Systems
Menna Mohsen, Lobna A. Said, Ahmed H. Madian, Ahmed G. Radwan, Ahmed S. Elwakil
Summary: Bio-impedance circuit modeling is a popular non-invasive technique used in medicine, biology, and agriculture to study the biophysical and biochemical changes in tissues by fitting impedance data. Variations in impedance magnitude and phase at different frequencies reflect these changes. This paper compares different fractional-order circuit models and methods for identifying parameters to best fit bio-impedance data.
Article
Engineering, Electrical & Electronic
Pipat Prommee, Peradol Pienpichayapong, Narongsak Manositthichai, Natapong Wongprommoon
Summary: This research presents a method to realize fractional-order devices or constant phase element (CPE) using continued fraction expansion and rational function approximation methods. The proposed CPE can function as fractional-order capacitor and inductor, with independently tunable impedance and operation frequency. The validation of the proposed fractional-order device on electrical Cole models of skull tissues shows comparable characteristics to the theoretical models.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Arpita Priyadarsini Dikshit, Chinmaya Mishra, Dibyaranjan Das, S. K. S. Parashar
Summary: This paper investigates the fractional order behavior of ZnO ceramics at different frequencies. The ZnO ceramic was prepared using high energy ball milling technique and sintered at 1300 degrees C. The study examined the frequency response properties (impedance and phase angles) using impedance analyzer. The results showed constant phase angles at low temperature ranges, and the structural and morphological composition of the ZnO ceramic was investigated using X-ray diffraction techniques and FESEM.
MATERIALS CHEMISTRY AND PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Chunling Hao, Faqiang Wang
Summary: This paper investigates a new implementation of a passive fractional-order capacitor (FOC) using a single-component fractional-order inductor (FOI). The approach provides a more accurate and realistic representation of the fractional-order impedance characteristic by avoiding the approximation of the integer-order transfer function. The paper also presents the realizable conditions of the passive FOC and analyzes the sensitivity of the impedance on component parameters, facilitating the design of the FOC emulator. The proposed method shows improved accuracy and the effectiveness is validated through simulations and experiments.
INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS
(2023)
Article
Computer Science, Information Systems
Mary Ann George, Ahmed S. Elwakil, Anis Allagui, Costas Psychalinos
Summary: Complex-order PI/PID controllers are designed to control the speed of an induction motor drive and an electric vehicle, offering greater flexibility, robustness, and improved system performance compared to conventional controllers. The controllers are approximated using the Sanathanan Koener iterative method due to the unavailability of commercial complex-order fractance elements. The approximated transfer function can be easily implemented using the AN231E04 Field Programmable Analog Array, and simulation and experimental results show good agreement with theoretical expectations.
Article
Engineering, Electrical & Electronic
Li Zhang, Aslihan Kartci, Hakan Bagci, Khaled N. Salama
Summary: Interest in fractional-order inductors (FOIs) has recently increased due to their ability to design accurate and robust models of dynamical systems. This work proposes a simple-to-realize FOI design with variable constant phase angle (CPA) to address the challenge of practical implementation.
INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Stavroula Kapoulea, Costas Psychalinos, Ahmed S. Elwakil
Summary: The main goal of this work is to approximate a general double exponent fractional-order transfer function using different tools to derive various types of filters. The investigated approximation tools include curve fitting based tools or the Pade approximation tool, resulting in easily implementable rational integer-order polynomials.
CIRCUITS SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Mathematics, Applied
Shibendu Mahata, Norbert Herencsar, David Kubanek, I. Cem Goknar
Summary: This paper introduces a new technique for optimally designing fractional-order Butterworth low-pass filters in the complex F-plane. The improved accuracy of the proposed scheme is demonstrated through experimental verification. A mixed-integer genetic algorithm is used to optimize the frequency responses of the fractional-order capacitor emulators.
FRACTIONAL CALCULUS AND APPLIED ANALYSIS
(2022)
Article
Engineering, Electrical & Electronic
Ahmed Elwakil, Costas Psychalinos, Brent Maundy, Anis Allagui
Summary: This study explores the possibility of synthesizing capacitive impedances with complex orders and explains the significance of such impedances. The applications of a complex order integrator and a complex order high-pass filter are demonstrated using circuit simulation results.
INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Costas Psychalinos, Abdullah Yesil, Shahram Minaei, Panagiotis Bertsias
Summary: This work investigates and proposes second-generation voltage conveyor structures based on flipped voltage follower stages. The proposed core offers extremely low or electronically adjustable input resistance and programmable outputs, enhancing the design flexibility and versatility of this active cell. Two design examples, including a multi-phase sinusoidal oscillator topology and an electronically adjustable first-order low-pass filter, are presented with simulation and experimental results.
CIRCUITS SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Engineering, Electrical & Electronic
Anis Allagui, Ahmed S. Elwakil, Chunlei Wang
Summary: This paper aims to demonstrate the four possible mapping functions for voltage or charge inputs and their corresponding time-domain or frequency-domain electrical charge outputs when a capacitive device is voltage-charged. Similarly, there are four more possible combinations when the device is current-charged. The dual relationship between each pair of functions is established using single or double Fourier transforms. All eight system functions align only if a constant time- and frequency-independent capacitance is assumed.
IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
(2023)
Article
Engineering, Electrical & Electronic
Panagiotis Bertsias, Costas Psychalinos, Shahram Minaei, Abdullah Yesil, Ahmed S. Elwakil
Summary: This work demonstrates the equivalence of fractional-order inverse filters with fractional-order controllers. By appropriately rewriting the filters transfer functions, the correspondence between the gain and time-constant of the filters and the scaling factor and differentiation/integration constant of the controllers is clarified. Possible implementations of fractional-order inverse filters using second generation voltage conveyors are presented, and an application example related to the control of a motion system is demonstrated to evaluate the behavior of the introduced structures.
MICROELECTRONICS JOURNAL
(2023)
Article
Electrochemistry
Abdulwadood Al-Ali, Ahmed S. Elwakil, Brent Maundy, Sohaib Majzoub, Anis Allagui
Summary: Electrochemical Impedance Spectroscopy (EIS) is an important diagnostic and monitoring tool in various industries. However, using the conventional frequency-sweep method for EIS in low and ultra low sub-Hz frequencies results in long measurement time. To overcome this issue, a wide-band signal covering the entire frequency range of interest is proposed and validated in this study using the Rudin-Shapiro polynomial. The signal was applied to an RC circuit and compared with the classical frequency-sweep method for verification, and then used for measuring strawberry bio-impedance for age monitoring applications.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2023)
Article
Chemistry, Analytical
Anis Allagui, Mohammed E. Fouda, Ahmed S. Elwakil, Costas Psychalinos
Summary: This study demonstrates a method to accurately estimate the time-domain power and energy of supercapacitors in response to excitation signals, using only the frequency-domain impedance parameters of the device. The results from simulations and experiments show the feasibility and potential of the proposed procedure.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Computer Science, Information Systems
Alexandros Pagidas, Costas Psychalinos, Ahmed S. Elwakil
Summary: The frequency behavior of fractional-order, power-law, and double-order filters can be approximated by the same rational integer-order transfer function through curve fitting. Additionally, their implementation can be achieved by the same core with changes in time constants and scaling factors. These findings are experimentally verified using a Field Programmable Analog Array device.
Article
Computer Science, Information Systems
Julia Nako, Costas Psychalinos, Ahmed S. Elwakil, Shahram Minaei
Summary: Non-integer order filters can be derived from a generalized structure presented in this work, including fractional-order and power-law filters. These filters can be implemented using a Current Feedback Operational Amplifier as the active element, and can be synthesized using Foster or Cauer RC networks.
Article
Computer Science, Information Systems
Fabian Khateb, Montree Kumngern, Tomasz Kulej, Viera Stopjakova, Costas Psychalinos
Summary: This paper presents a new versatile first-order voltage-mode analog filter using a single multiple-input voltage differencing differential difference amplifier for extremely low-voltage supply and low-frequency applications. The filter can realize multiple transfer functions and has high input and low output impedance, making it suitable for voltage-mode circuits. The filter's pole frequency can be controlled electronically.
Article
Computer Science, Information Systems
Julia Nako, Costas Psychalinos, Ahmed S. Elwakil, Drazen Jurisic
Summary: In this work, higher-order fractional filters with fully controllable frequency characteristics are realized by fitting the filter's magnitude response using a minimum-phase state-space model. Rational integer-order transfer functions are then derived and implemented using Operational Transconductance Amplifiers (OTAs) and a Field Programmable Analog Array (FPAA) device as active elements. The implemented filters can be easily validated on the digitally programmable FPAA platform and have electronic adjustability of their type, order, and characteristic frequencies.
Article
Engineering, Electrical & Electronic
Wenzhang Zhang, Jinyao Zhang, Chaoyun Song, Rui Pei, Xuanming Zhang, Haiwen Liu, Congzheng Han, Yi Huang, Jiafeng Zhou
Summary: Due to the low available ambient power level, it is desirable to have a high gain and wide beamwidth antenna. However, it is difficult to achieve both simultaneously. In this study, a multi-port antenna using a nonuniform metasurface is proposed to overcome this limitation. By exciting three modes with complementary radiation patterns, and connecting each feed to a rectifier, the antenna achieves a wide beam and high gain effectively. The proposed rectenna has a beamwidth of 114 degrees with a gain ranging from 8 to 9.8 dBi, and an RF-to-DC conversion efficiency of 3%-67% at 2.45 GHz.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Shangjing Xi, Kai-Da Xu, Shuai Yang, Xue Ren, Wen Wu
Summary: This paper proposes a bandpass frequency selective surface (FSS) with low loss and angular stability based on three metal layers. The FSS structure is built by coupling the top and bottom resonant layers through a metal ring layer. The performance of the FSS is insensitive to the polarization and angle of the incident wave, and the prototype measurements agree with the simulations.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Ibrahim Abuishmais, Hani H. Ahmad, Fadi. R. Shahroury
Summary: This paper presents a WLED driver solution for multi-display screen systems, featuring a single-inductor power stage with independent outputs and multiple WELD strings with independent digital brightness/dimming control for each display. The inclusion of high-side switches enables independent output voltage control and minimized power consumption.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Rawaa Maher, Ahmed Allam, Haruichi Kanaya, Adel B. Abdelrahman
Summary: This paper presents two high-gain, dualband antennas designed to harvest energy from GSM-1800 and the 2.45 GHz ISM frequency bands. The antennas demonstrate good gain and circular polarization characteristics. Additionally, a dualband rectifier is designed to achieve high peak conversion efficiency.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Trapti Sharma, Addagatla Prashanth, Srinivas Bachu, Deepa Sharma, Anil Kumar Sahu
Summary: This article presents two architectures for ternary Schmitt trigger designs based on carbon nanotube technology. The proposed designs demonstrate superior performance in terms of power consumption and power delay product compared to similar designs, and show stability under process variations. These designs have the potential to achieve higher information density and lower power consumption in digital computation.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Tolga Yucehan
Summary: This manuscript introduces an ICFOA-based lossless floating immittance simulator (FIS). The FIS realizes floating capacitance multiplier, simulated floating inductor, and floating frequency-dependent negative resistor through selection of passive elements. Simulation results confirm the ideal performance of the proposed circuit within certain frequency ranges.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Kumar Saurabh, Sukwinder Singh
Summary: This article introduces a method to improve the performance of a power amplifier. By calculating the optimal load and source impedances through source and load-pull analysis, and designing the optimal matching architecture of input and output network using neural network algorithm, the power amplifier achieves high efficiency and gain in the frequency range of 13.75 GHz-14.5 GHz.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Zhengjia Wang, Yongqing Leng, Xin Qiu, Ming Hui, Youbo Jing, Demin Cao
Summary: This paper proposes a novel reconfigurable filter that can flexibly tune both the center frequency and bandwidth simultaneously. The filter consists of a filter network with Chebyshev properties and a parallel resonator. Through simulation and experiments, it has been proven that this reconfigurable filter has a tunable frequency coverage range of 0.4-2 GHz, with a large tunable range.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Audrey Cayron, Christophe Viallon, Ayad Ghannam, Alessandro Magnani, Thierry Parra
Summary: A 4x4 Butler matrix for millimeter-wave communications is presented in this paper, which utilizes a new 3-D Integrated Passive Devices (IPD) process to achieve a higher performance/compactness trade-off. The design incorporates 3-D transformers and solenoids to optimize couplers and phase shifters and results in a wide bandwidth and low insertion loss.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Abdelali Agouzoul, Emmanuel Simeu, Mohamed Tabaa
Summary: This study aims to improve energy efficiency in buildings, specifically in heating control. By utilizing a model predictive control system based on artificial neural network models and advanced technologies such as FPGAs, the study successfully achieved a significant reduction in heating energy consumption in buildings.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Amjad Iqbal, Muath Al-Hasan, Ismail Ben Mabrouk, Pererik Andreasson, Emil Nilsson, Amor Smida, Tayeb A. Denidni
Summary: This study proposes a compact and frequency-adjustable/reconfigurable substrate integrated waveguide antenna for duplex wireless communications. The antenna achieves frequency reconfigurability and high isolation through the use of resonators and dielectric materials. It has stable radiation properties and a wide frequency range, making it suitable for compact reconfigurable devices.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Peyman PourMohammadi, Hassan Naseri, Noureddine Melouki, Fahad Ahmed, Qi Zheng, Amjad Iqbal, Guy A. E. Vandenbosch, Tayeb A. Denidni
Summary: This article presents a novel low-profile self-duplexing antenna with high isolation for out-band operation applications. The antenna features two patches, one rectangular and one triangular, both utilizing the quarter-mode substrate integrated waveguide (QMSIW) cavity for enhanced performance. Miniaturization is achieved through capacitive slots. The antenna operates at both 5.8 and 9.8 GHz frequencies, with impressive alignment between measured and simulated results. It has compact dimensions and 40 dB isolation between its ports, as well as consistent radiation patterns at both frequencies. The gains at 5.8 and 9.8 GHz are 4.1 and 4.6 dBi, respectively. The antenna's frequency bands can be independently tuned by adjusting the size of the capacitive slots. The article also provides valuable insights into the antenna's functionality and versatility, making it a valuable asset for dual-band wireless communication applications.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Duy-Thai Nguyen, Thanh-Hai Le, Van-Sang Doan, Van-Phuc Hoang
Summary: This paper proposes a method that combines UNet and rootMUSIC algorithm to improve the accuracy of DOA estimation. By converting the covariance matrix of received signals into an ideal antenna array's covariance matrix, and then using rootMUSIC algorithm for DOA estimation, the experimental simulation results show that this method can significantly reduce the error of DOA estimation compared with traditional methods.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Shafaq Kausar, A. U. Kausar, Muhammad Usman Hadi, Hani Mehrpouyan
Summary: This paper presents the design of a high gain multi-beam transmitarray antenna, which is capable of independently steering multiple beams in the azimuth and elevation plane. By using a passive meta-surface, the antenna achieves continuous beam steering by adjusting the phase of the unit cell transmission coefficient. The designed antenna is low cost, robust, and suitable for satellite communication and mm-Wave 5G systems.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)
Article
Engineering, Electrical & Electronic
Jeong-Hun Park, Kyeong-Jun Lee, Seung-Jun Park, Moon-Que Lee
Summary: A new self-oscillating mixer (SOM) has been proposed in this paper, which includes a dielectric resonator (DR) antenna fed by a half-mode substrate integrated waveguide (HMSIW) on an FR4 epoxy substrate using hybrid integrated circuit technique. The high quality factor of the HMSIW resonator and the higher order HEM13 delta mode excitation of the DR radiator contribute to the excellent phase noise performance of the oscillator and the high directivity of the antenna, respectively. The phase noise, estimated LO power, and conversion gain are -102.5 dBc/Hz at 1 MHz offset, 8.74 dBm at an oscillation frequency of 24.15 GHz, and 8.5 dB, respectively. The figure-of-merit for the oscillator is -172.8 dBc/Hz.
AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS
(2024)