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315 results on '"Rahim, Mohamad Kamal A."'

104. Complementary split-ring resonator and strip-gap based metamaterial fractal antenna with miniature size and enhanced bandwidth for 5G applications.

Author

Karimbu Vallappil, Arshad, A. Rahim, Mohamad Kamal, A. Khawaja, Bilal, Iqbal, Muhammad Naeem, Murad, Noor Asniza, Gajibo, Mohamed Musthapa, O. Nur, Levy, and S. Nugroho, Bambang

Subjects
*METAMATERIAL antennas, *RESONATORS, *5G networks, *MICROSTRIP antennas, *BANDWIDTHS, *ANTENNAS (Electronics)
Abstract

This paper proposes two different types of metamaterial (MTM) antennas for fifth-generation (5G) mid-band frequency operation. The radiating patch of the proposed antenna is based on the combined Minkowski-Sierpinski carpet fractal structure. On the ground plane, two different types of MTM structures: Complementary split-ring resonator (CSRR), and Strip-gap are etched to enhance the overall bandwidth and gain of the antenna. The introduction of these structures on the ground plane also leads to antenna miniaturization. Both the proposed MTM structure based antennas resonate at 3.5GHz. The overall size of the two fabricated prototypes is 28×29.5 mm2 / 28×28.5 mm2, which shows the compactness of the proposed design by 43% / 42% as compared to the conventional microstrip patch antenna (MPA). The measured bandwidth/gain achieved by the proposed combined Minkowski-Sierpinski carpet fractal antenna (CMSFA) having CSRR MTM and strip-gap etched on the ground plane are 370 MHz / 2.42dBi and 440 MHz / 3.75dBi, respectively. [ABSTRACT FROM AUTHOR]

Published
2022
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116. Wideband Planar Microstrip Antenna Based on Split Ring Resonator For 5G Mobile Applications.

Author

Keriee, Hussam, Rahim, Mohamad Kamal A., Ayop, Osman, Nayyef, Nawres Abbas, Al-Gburi, Ahmed Jamal Abdullah, Esmail, B. A. F., and Abbas, Syed Muzahir

Subjects
MICROSTRIP antennas, METAMATERIAL antennas, PLANAR antennas, MOBILE apps, RESONATORS, 5G networks, METAMATERIALS
Abstract

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2021
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119. Leaf-Shaped Textile Dipole Antenna Design

Author

Ramly, Nurul Jannah, primary, Rahim, Mohamad Kamal A, additional, Samsuri, Noor Asmawati, additional, Yusoff, Mohd Fairus Mohd, additional, Ismail, Muhammad Faizal, additional, and Majid, Huda A, additional

Published
2019
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127. Metamaterial Based Compact Branch-Line Coupler with Enhanced Bandwidth for Use in 5G Applications.

Author

Vallappil, Arshad K., Rahim, Mohamad Kamal A., Khawaja, Bilal A., and Aminu-Baba, Murtala

Subjects
*BANDWIDTHS, *ANTENNA arrays, *CAPACITORS, *PORT districts
Abstract

A novel compact 5G branch-line coupler (BLC) based on open-circuit coupled-lines and interdigital capacitor structure is presented in this paper. The proposed BLC shows the composite right/left handed (CRLH) metamaterial transmission-line (TL) operation. The proposed BLC is designed and simulated using CST microwave studio. The designed BLC is then fabricated using the FR4 substrate (er = 4.3 and h = 1.66mm). The proposed 5G BLC with coupled-lines and the interdigital capacitor has achieved the fractional bandwidth of ~ 40.2% and the size reduction of 54% as compared to the conventional BLC. The fabricated BLC operates at 2.74 - 4.15GHz frequency band with a coupling factor of -3 ± 0.2dB and the phase difference of 88o between the output ports. The BLC measurements are performed at the operating frequency of 3.5GHz. The simulated and measured scattering parameters and phase difference results are in good agreement with each other. The proposed design is suitable for use in future butler-matrix based beamforming networks for antenna array systems in 5G wireless applications. [ABSTRACT FROM AUTHOR]

Published
2020

128. Wideband Metamaterial Antenna Design

Author

Iliyasu, Adamu Y, primary, Hamid, Mohamad Rijal, additional, Rahim, Mohamad Kamal A, additional, Samsuri, Noor Asmawati, additional, Yusoff, Mohd Fairus Mohd, additional, Ismail, Muhammad Faizal, additional, and Majid, Huda A, additional

Published
2018
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141. Single-, Dual- and Triple-band Frequency Reconfigurable Antenna

Author

Idris, Izni Husna, Hamid, Mohamad Rijal, Jamaluddin, Mohd Haizal, Rahim, Mohamad Kamal A., Kelly, James R., and Majid, Huda A.

Subjects
slot antenna, Frequency reconfigurable antenna, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The paper presents a frequency reconfigurable slot dipole antenna. The antenna is capable of being switched between single-band, dual-band or triple-band operation. The antenna incorporates three pairs of pin-diodes which are located within the dipole arms. The antenna was designed to operate at 2.4 GHz, 3.5 GHz and 5.2 GHz using the aid of CST Microwave Studio. The average measured gains are 1.54, 2.92 and 1.89 dBi for low, mid and high band respectively. A prototype was then constructed in order to verify the performance of the device. A good level of agreement was observed between simulation and measurement.

Published
2014

144. An Electronically Reconfigurable Patch Antenna Design for Polarization Diversity with Fixed Resonant Frequency

Author

Osman, Mohamed Nasrun, Rahim, Mohamad Kamal A., Gardner, Peter, Hamid, Mohamad Rijal, Yusoff, Mohd Fairus Mohd, Majid, Huda A., Osman, Mohamed Nasrun, Rahim, Mohamad Kamal A., Gardner, Peter, Hamid, Mohamad Rijal, Yusoff, Mohd Fairus Mohd, and Majid, Huda A.

Abstract

In this paper, an electronically polarization reconfigurable circular patch antenna with fixed resonant frequency operating at Wireless Local Area Network (WLAN) frequency band (2.4-2.48 GHz) is presented. The structure of the proposed design consists of a circular patch as a radiating element fed by coaxial probe, cooperated with four equal-length slits etched on the edge along x-axis and y-axis. A total of four switches was used and embedded across the slits at specific locations, thus controlled the length of the slits. By activating and deactivating the switches (ON and OFF) across the slits, the current on the patch is changed, thus modifying the electric field and polarization of the antenna. Consequently, the polarization excited by the proposed antenna can be switched into three types, either linear polarization, left-hand circular polarization or right-hand circular polarization. This paper proposes a simple approach that able to switch the polarizations and excited at the same operating frequency. Simulated and measured results of ideal case (using copper strip switches) and real case (using PIN diode switches) are compared and presented to demonstrate the performance of the antenna.

Published
2015

145. Textile Diamond Dipole and Artificial Magnetic Conductor Performance under Bending, Wetness and Specific Absorption Rate Measurements

Author

Kamardin, Kamilia, Rahim, Mohamad Kamal A., Hall, Peter S., Samsuri, Noor Asmawati, Jalil, Mohd Ezwan, Abd Malek, Mohd Fareq, Kamardin, Kamilia, Rahim, Mohamad Kamal A., Hall, Peter S., Samsuri, Noor Asmawati, Jalil, Mohd Ezwan, and Abd Malek, Mohd Fareq

Abstract

Textile diamond dipole and Artificial Magnetic Conductor (AMC) have been proposed and tested under wearable and body centric measurements. The proposed antenna and AMC sheet are entirely made of textiles for both the substrate and conducting parts, thus making it suitable for wearable communications. Directive radiation patterns with high gain are obtained with the proposed AMC sheet, hence minimizing the radiation towards the human body. In this study, wearable and body centric measurements are investigated which include bending, wetness and Specific Absorption Rate (SAR). Bending is found not to give significant effect to the antenna and AMC performance, as opposed to wetness that yields severe performance distortion. However, the original performance is retrieved once the antenna and AMC dried. Moreover, notable SAR reduction is achieved with the introduction of the AMC sheet, which is appropriate to reduce the radiation that penetrates into human flesh.

Published
2015

147. Wideband P-Shaped Dielectric Resonator Antenna

Author

Khalily, Mohsen, Rahim, Mohamad Kamal A., Kishk, Ahmed A., and Danesh, Shadi

Subjects
Dielectric resonator antenna, wideband, Q factor, P shape
Abstract

A novel P-shaped dielectric resonator antenna (DRA) is presented and investigated for wideband wireless application. By using P-shaped resonator, a wideband impedance bandwidth of 80% from 3.5 to 8.2 GHz is achieved. The antenna covers all of wireless systems like C-band, 5.2, 5.5 & 5.8 GHz-WLAN & WiMax. The proposed antenna has a low profile and the thickness of the resonator is only 5.12 mm, which is 0.06-0.14 free space wavelength. A parametric study is presented. The proposed DRA is built and the characteristics of the antenna are measured. Very good agreement between numerical and measured results is obtained.

Published
2013

148. Performance Evaluation of two Port and four Port Measurement for Twisted Pair Cable.

Author

Asrokin, Azhari Bin and Rahim, Mohamad Kamal Bin A.

Subjects
PORT districts, PERFORMANCE evaluation, HARBORS, CABLES, MEASUREMENT, HARBOR management
Abstract

A balance-unbalance (balun) transformer is commonly used to connect the balance 100 Ohm twisted pair cable to the unbalance 50 Ohm network analyzer ports, but due to the limitations of the core (i.e. ferrite) inside the balun, the balun can only effectively operates at a certain band of frequencies. This limitation can be eliminated by using a 4-port vector network analyzer (VNA) which is done by connecting the VNA’s ports to each conductor end. The extracted S-parameters will then be transformed to a 2-port S-parameters in differential mode at both ports. To validate the measurement technique, S-parameter measurement by using the 4-Port Network Analyzer without any balun will be compared to the measurement which used the 2-Port Network Analyzer with the balun transformers. Two twisted pair cable distances are selected as reference which are 500, and 1000 meters with nominal copper diameter of 0.5mm. Based on the measurement results, the 4-ports measurement shows good correlation with the 2-ports measurement especially at 500m distance. This shows that the 4-ports measurement setup is suitable to be used to measure twisted pair copper cable and possible to measure at a higher frequency band such as up to 500 MHz but at a shorter twisted pair cable distance. [ABSTRACT FROM AUTHOR]

Published
2018
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149. A multi to wideband frequency reconfigurable antenna.

Author

Idris, Izni Husna, Hamid, Mohamad Rijal, Kamardin, Kamilia, and Rahim, Mohamad Kamal A.

Subjects
SLOT antennas, ULTRA-wideband antennas, PIN diodes, COGNITIVE radio, ANTENNA radiation patterns
Abstract

Abstract: A frequency reconfigurable antenna with a simple design structure and biasing circuit is presented. The antenna is able to configure its frequencies to operate either in multiband or wideband modes. The antenna is fed by a coplanar waveguide transmission line. The reconfiguration characteristics of the antenna is achieved by using PIN diode switches. The operating frequencies of the multiband mode are designed within the wideband mode operating range, from 2 to 6 GHz. Both simulated and measured results of S11, radiation pattern and realized gains are verified. The antenna allows a degree of freedom in providing the frequency reconfiguration from multiband to wideband mode and vice versa. [ABSTRACT FROM AUTHOR]

Published
2018
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150. Single-band and Dual-band Artificial Magnetic Conductor Ground Planes for Multi-band Dipole Antenna

Author

Abu, Maisarah and Rahim, Mohamad Kamal A.

Subjects
printed dipole antenna, high impedance surface, RFID and zigzag AMC, Artificial Magnetic Conductor (AMC)
Abstract

Two new designs of high impedance surface (HIS) structure are presented, namely zigzag and slotted rectangular with I-shaped slot Artificial Magnetic Conductor (AMC). The zigzag AMC is designed based on the straight dipole AMC. The zigzag AMC is introduced to minimize the AMC size and to be suitable for UHF RFID applications. On the other hand, the slotted rectangular with I-shaped slot AMC is designed to operate at 0.92 GHz and 2.45 GHz. The slot is loaded in the main patch of the AMC to create the other resonant frequency. By using this technique the resonant frequency can be lowered, and hence reduce the size of the AMC. Both structures are designed using the same dielectric substrate that is Taconic TLC-32. The properties of the AMC are investigated such as the reflection phase, reflection magnitude and surface impedance. The designed AMCs then are used as a back plane for the printed multi-band dipole antenna. By introducing the AMC as a ground plane (GP) for the printed dipole antenna, the gain of the dipole antenna is increased.

Published
2012

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