Kamilia Kamardin
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.
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.
Performance analysis of patch antenna for underwater wireless communication in seawater Siti Harliza Mohd Razali; Razali Ngah; Yoshihide Yamada; Kamilia Kamardin
Indonesian Journal of Electrical Engineering and Computer Science Vol 22, No 2: May 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v22.i2.pp857-865

Abstract

Underwater wireless communication in seawater is becoming more interesting and challenging in recent years. The development of antenna for underwater wireless communication in seawater at 900 MHz UHF range frequency is implemented by using patch antenna. In this paper, the antennas were designed using FEKO, an electromagnetic simulation software, and a suitable size for rectangular patch antenna for seawater application was developed to study the relevance between λ0 with W and L in seawater. The difference between the patches in free space and seawater was the L size, which was slightly bigger, about 0.9 mm, than free space size. But the gain for patch antenna in seawater was found at -2.51 dBi, lower than patch antenna in free space, which was 5.76 dBi due to the path loss in seawater. This shows that attenuation happened, and a better antenna will be design. The one that has better gain, which is around above 2 dBi in seawater, in order to get better performance antenna in seawater environment.
Performance analysis comparison between non mixed-criticality and mixed-criticality system in microcontroller Siti Nurhafizza Maidin; Noor Azurati Ahmad; Kamilia Kamardin; Shamsul Sahibuddin; Syahrizal Fadhlie Sabri
Indonesian Journal of Electrical Engineering and Computer Science Vol 15, No 2: August 2019
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v15.i2.pp678-687

Abstract

Nowadays, implementation of real-time embedded system or safety-critical in a real-time system is significant within emerging technologies because the system involves many aspects such as safety and task execution without missing deadlines. The main cause of implementation is to avoid catastrophic loss. Besides that, effectuation of the mixed-criticality system in embedded system making system more complex for task execution. For an embedded system, the main component involves real-time scheduling. The implementation of DPM method in real-time scheduling is well known, but in the mixed-criticality system, DPM method is still lacking. In order to cater this problem, Dynamic Power management (DPM) method is deployed onto the microcontroller of the mixed-criticality system to save energy when executing tasks in order to have better performance in the system. The usage of the DPM method in mixed-criticality of microcontroller resulting decrease of 0.82% in LED output voltage value meanwhile, for the LCD output, the voltage value decreased by 1.37% in the home alarm system. Thus, the energy-saving in the microcontroller of the mixed-criticality system using the DPM method is defined.
Near-field microwave focusing evaluation of dielectric lens antenna for human body model Amirah Abd Rahman; Kamilia Kamardin; Yoshihide Yamada; Masaharu Takahashi
Indonesian Journal of Electrical Engineering and Computer Science Vol 29, No 1: January 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v29.i1.pp161-173

Abstract

Various small focus spot applicators are being investigated for hyperthermia therapy, which requires microwave concentration to heat tumors in the human body. Dielectric lens antenna is frequency independent and has strong focusing capability to achieve a very small focusing spot. In this paper, lenses with diameters of 30, 50 and 70 cm were designed to evaluate the size of the focal spot in the human body model. The electromagnetic simulator, FEKO was used to generate rays and near-field focusing data of dielectric lenses at a frequency of 2.45 GHz. The simulated focal spot sizes agreed well with the theoretical values. An analytical investigation into the power at the focal spot was conducted using the proposed power relations of the focused lens novel equation. The theoretical propagation loss is used to represent the power density degradation at the focal spot caused by microwave absorption by the human body. The simulation results of the focused lens in the human body indicated that the 30 cm lens achieved a larger focal spot with a greater focusing power, 0.714 mW compared to the 70 cm lens, which achieved a smaller focal spot but a lower focusing power, which was 0.393 mW.