Mohamad Rijal Hamid
Universiti Teknologi Malaysia

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Band-pass Filter with Harmonics Suppression Capability Izni Husna Idris; Mohamad Rijal Hamid; Kamilia Kamardin; Mohamad Kamal A. Rahim; Farid Zubir; Huda A. Majid
International Journal of Electrical and Computer Engineering (IJECE) Vol 8, No 4: August 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (716.161 KB) | DOI: 10.11591/ijece.v8i4.pp2512-2520

Abstract

This paper presents a Band-pass Filter (BPF) with a very wide suppressions band. The filter design is based on a modified U-shaped slot. Two pair of U-shaped slots is used to ensure that the filter can suppress the unwanted frequencies up to 4th harmonics. In order to achieve sharp skirt, two transmission zeroes are created near the passband area. Additional transmission zeroes are introduced to deepen the stopband area. Therefore, the passband range starts from 1.3 to 3.3 GHz and the stopband range from 3.3 GHz up to 9 GHz are achieved. The filter performances are verified through simulated and measured results.
Circular polarization folded reflectarray antenna for 5G applications Mohd Fairus Mohd Yusoff; Lim Jit Min; Mohamad Rijal Hamid; Zaharah Johari; Muhammad Naeem Iqbal
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 17, No 5: October 2019
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v17i5.12812

Abstract

Fifth-generation (5G) is a wireless connection built specifically to keep up with the rapid increase of devices that need a mobile internet connection. A system working on 5G band can provide higher bandwidth and faster data rate as compared to fourth-generation (4G) band. Thus, an antenna with higher gain and lower profile is required to support this system. On the other hand, the performance of circular polarization antenna is better than linear polarization antenna due to its ability to accept wave from different direction. In this project, a low profile circular polarization folded reflectarray antenna with operating frequency of 28 GHz is presented. This project is divided into two parts. In the first part, a linear polarization folded reflectarray antenna is designed. In this second part, a meander lines polarizer is used to convert the linear polarization antenna to circular polarization antenna. The antenna is fed by a linear polarized waveguide. Each radiating element of the antenna is in rectangular shape. The size of the radiating elements are selected according to obtain required phase delay to form a planar phase front in the far-field distance. Both of the antennas are simulated by using Computer Simulation Technology (CST) software. Finally, the results shows excellent performances with 16.81dB directivity and 1.49dB axial ratio at 28GHz. Thus, the antenna is very suitable for 5G applications.
Wideband Frequency Selective Surface Based Transmitarray Antenna at X-Band Muhammad Naeem Iqbal; Mohd Fairus Mohd Yusoff; Mohammad Kamal A Rahim; Mohamad Rijal Hamid; Farid Zubir; Zaharah Johari; Huda Bin A Majid
Indonesian Journal of Electrical Engineering and Informatics (IJEEI) Vol 8, No 3: September 2020
Publisher : IAES Indonesian Section

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52549/ijeei.v8i3.1270

Abstract

In this paper, a wideband multilayer transmitarray antenna is designed for Ku frequency band. The unit cell is designed at 12GHz using frequency selective surface structure. Double square ring with center patch based multilayer unit cell is simulated. The effect of substrate thickness variation on transmission coefficient magnitude and phase range is discussed. The horn antenna designed at X-band will be used as feed source for transmitarray antenna. Transmitarray simulation results show wide impedance bandwidth from 10 to 13GHz. Wide gain bandwidth of 1.975GHz with peak gain of 18.96dB is achieved. The proposed transmitarray design will find applications in high gain, directional, low profile antennas for X-band communication systems.
A multiband and wideband frequency reconfigurable slotted bowtie antenna Izni Husna Idris; Mohamad Rijal Hamid; Kamilia Kamardin; Mohamad Kamal A. Rahim; Huda A. Majid
Indonesian Journal of Electrical Engineering and Computer Science Vol 19, No 3: September 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v19.i3.pp1399-1406

Abstract

A multiband and wideband frequency reconfigurable antenna is presented. A wideband from 3.5 GHz to 9.0 GHz is achieved by introducing one stripline in the middle of a slotted bowtie antenna, whereas multiband is obtained by integrating an additional two slotted arms at the end of bowtie-shaped. As a result, the antenna operated at multiband mode (1.7 GHz and 2.6 GHz) and wideband mode (3.5 GHz to 9.0 GHz) simultaneously. The reconfigurability of the antenna is attained through switches. Five states are achieved with three  pairs of switches configurations. All results are presented and discussed, including S11, current distribution, radiation pattern, and gain. The antenna is suitable to be used in multimode communication systems.
Indoor Channel Capacity Measurement of 2 x 2 MIMO Polarization Diversity Antenna Mohamed Nasrun Osman; Mohamad Kamal A. Rahim; Mohamad Rijal Hamid; Mohd Fairus Mohd Yusoff; Mohamad Zoinol Abidin A. Aziz; Muzammil Jusoh; Muhammad Azfar Abdullah; Nursaidah Muhamad Nadzir
Indonesian Journal of Electrical Engineering and Computer Science Vol 10, No 3: June 2018
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v10.i3.pp1196-1202

Abstract

This paper presents the channel capacity investigation and the polarization reconfigurable antenna analysis for MIMO system in an indoor scenario. A single and dual-port polarization reconfigurable antenna is used at the receiver end to study the effect of polarization diversity configurations towards the achievable performance of the channel capacity. The polarization reconfigurable antennas are developed through two techniques, which are slits perturbation for single-port and feeding network modification for dual-port. The benefits offered by the designed antennas are investigated when being used as a receiver in both line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. The results show the proposed antennas are suitable to be adopted and highly potential to improve the channel capacity of the MIMO systems.