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A novel slotted antenna design for future Terahertz applications Youssef, Amraoui; Halkhams, Imane; El Alami, Rachid; Ouazzani Jamil, Mohammed; Qjidaa, Hassan
International Journal of Electrical and Computer Engineering (IJECE) Vol 14, No 3: June 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v14i3.pp2708-2716

Abstract

A slotted patch antenna operating at 118 GHz is proposed to address challenges in the terahertz (THz) frequency band for wireless communication systems. The antenna design, utilizing a Rogers RO3003 substrate, which has a dielectric constant of ???????? = 3 and tan ???? = 0.001, strategically incorporates slots to enhance key performance parameters. Copper is employed for the ground and radiating patch, and a microstrip feeding method powers the antenna. High frequency structure simulator (HFSS) software is used for design and simulation, revealing resonance at 0.118 THz with a reflection coefficient of -42.41 dB and an impedance bandwidth of 4.42 GHz (115.84–120.26 GHz). At the operating frequency, the antenna exhibits a gain of 7.36 dB, maximum directivity of 7.38 dB, the voltage standing wave ratio (VSWR) of 1.01, and 99.75% radiation efficiency, all within a compact size of 1.5×1.3×0.1 mm³. The suggested antenna outperforms recent counterparts, making it suitable for applications like security screening and wireless communication systems (5G). Future efforts will target bandwidth expansion, gain enhancement, and further size reduction to enhance overall performance.
A Li-ion battery charger based on LDO regulator with pre-charge mode in 180 nm CMOS technology Ouremchi, Mounir; El Khadiri, Karim; Qjidaa, Hassan; Jamil, Mohammed Ouazzani
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 15, No 2: June 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v15.i2.pp659-669

Abstract

This paper presents a novel Li-Ion battery charger that utilizes a low-dropout (LDO) regulator and incorporates four control modes: low constant current mode, pre-charge current mode, fast constant current mode, and constant voltage mode. The charger aims to meet specific criteria such as high precision, high efficiency, and small form factor. Through simulation results, the following specifications were obtained using a 1.8 V supply in a 0.18 μm complementary metal–oxide–semiconductor (CMOS) technology: a trickle current of 124.7 mA, a pre-charge current of 466.94 mA, a maximum charge current of 1.06 A, and a charge voltage of 4.21 V. The proposed charger demonstrates an efficiency of 92%.
Switching regulator based on an adaptive DC-DC buck converter for a lithium-ion battery charging interface Rahali, Ahmed; El Khadiri, Karim; Qjidaa, Hassan; Tahiri, Ahmed
IAES International Journal of Robotics and Automation (IJRA) Vol 13, No 3: September 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijra.v13i3.pp351-360

Abstract

A switching regulator based on an adaptive DC-DC buck converter for a Li-ion battery charging interface is introduced in this paper with the aim of improving the efficiency of charging the Li-ion battery during the whole charging process. By using the battery voltage as feedback, an adaptive reference is generated. This reference is employed by the converter, which is in continuous conduction mode (CCM), to produce a wide adaptive output voltage that closely tracks the battery voltage, intended to serve as the power source for the multimode charging interface. The converter was implemented in a 180 nm complementary metal oxide semiconductor (CMOS) process and simulated using the Cadence Virtuoso tool. With an input voltage of 5 V and a switching frequency selected at 500 kHz, the simulation results show that the converter produces different charging currents for each battery charging mode, and an adaptive output voltage ranging from 2.8 V to 4.38 V, with the current ripple of 38 mA in CC mode and voltage ripple factor less than 1% in constant voltage (CV) mode. The average converter efficiency is 83.5%.
High-efficiency multimode charging interface for Li-Ion battery with renewable energy sources in 180 nm CMOS Mamouni, Hajjar; El Khadiri, Karim; El Affar, Anass; Jamil, Mohammed Ouazzani; Qjidaa, Hassan
Indonesian Journal of Electrical Engineering and Computer Science Vol 38, No 2: May 2025
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v38.i2.pp744-754

Abstract

The high-efficiency multi-source Lithium-Ion battery charger with multiple renewable energy sources described in the present paper is based on supply voltage management and a variable current source. The goal of charging the battery in a constant current (CC) mode and controlling the supply voltage of the charging circuit are both made achievable using a variable current source, which may improve the battery charger’s energy efficiency. The battery must be charged with a degraded current by switching from the CC state for the constant voltage (CV) state to prevent harming the Li-Ion battery. The Cadence Virtuoso simulator was utilized to obtain simulation results for the charging circuit, which is constructed in 0.18 μm CMOS technology. The simulation results obtained using the Cadence Virtuoso simulator, provide a holding current trickle charge (TC) of approximately 250 mA, a maximum charging current (LC) of approximately 1.3 A and a maximum battery voltage of 4.2 V, and takes only 29 minutes to charge.