Muammar Mohamad Isa
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Preferred name
Muammar Mohamad Isa
Official Name
Muammar , Mohamad Isa
Alternative Name
Isa, M. M.
Mohamad Isa, M.
Isa, Muammar Mohamad
Mohamad Isa, Muammar
Isa, M. Mohamad
Main Affiliation
Scopus Author ID
57202563525
Researcher ID
N-2105-2017

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Remazol orange dye sensitized solar cell

2017-01-03 , Siti Salwa Mat Isa , Muhammad Mahyiddin Ramli , Nor Azura Malini Ahmad Hambali , Muda M.R. , Shahrir Rizal Kasjoo , Muammar Mohamad Isa , Nurul Izza Mohd Nor , Norhawati Ahmad , Nazuhusna Khalid , Nur M. Selamat , Nur Asyikin Mohd Anhar

Water based Remazol Orange was utilized as the dye sensitizer for dye sensitized solar cell. The annealing temperature of TiO2 working electrode was set at 450 °C. The performance of the device was investigated between dye concentrations of 0.25 mM and 2.5 mM at three different immersion times (3, 12 and 24 hours). The adsorption peak of the dye sensitizer was evaluated using UV-Vis-Nir and the device performance was tested using solar cell simulator. The results show that the performance was increased at higher dye concentration and longer immersion time. The best device performance was obtained at 0.2% for dye concentration of 2.5 mM immersed at 24 hours.

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Numerical Simulation and Characterization of Silicon Based OR Logic Gate Operation Using Self-Switching Device

2021-01-01 , Goh Y.X. , Zakaria N.F. , Tan Y.L. , Shahrir Rizal Kasjoo , Shaari S. , Muammar Mohamad Isa , Singh A.K.

Logic gates are the main components inside the integrated circuit used for almost every technological application. Nowadays, in order to enhance the performance of the smart device, while targeting in cut down of the fabrication cost and achieve low power consumption, lithography-based VLSI design technology on silicon are still being widely applied. Hence, an OR gate structure, a silicon based self-switching device (SSD) is introduced and investigated in this project. Such device is believed capable to act as an alternative for a low-powered logic gate application, suitable for CMOS devices. The SSD has an advantage in term of simplicity in fabrication process with a very low threshold voltage. Since SSD characteristics is similar to a conventional diode characteristic, the gate is designed in ATLAS Silvaco device simulator based on a diode logic to perform OR logic function after a validation of the physical and materials parameters. The electrical characterization and structural analysis were also done to observe the electrical performance and physical condition in the device. The simulated design showed a good OR logic output response with the inputs, and acceptable output ranged from around 4.5 to 4.8 V with 5 V HIGH inputs. The results from this OR gate characterization may assist in developing the logic gate for device integration and may act as a reference for future complex integrated circuit design.

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Gain enhancement of microstrip patch antenna using artificial magnetic conductor

2019-03-01 , Norfatihah Bahari , Jamlos M.F. , Muammar Mohamad Isa

The paper presents an artificial magnetic conductor (AMC) structure to enhance the gain of the double microstrip patch antenna. By placing this kind of metamaterial in between the two Rogers RT5880 substrates, the antenna achieved lots of improvement especially in terms of size miniaturization, bandwidth, return loss, gain and efficiency. The antenna is intended to operate at 16 GHz where the prospect fifth generation (5G) spectrum might be located. Integration of AMC structure into the proposed antenna helps to improve nearly 16.3% of gain and almost 23.6% of size reduction.

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Design and analysis of two stage CMOS operational amplifier using 0.13 μm technology

2020-01-08 , Tan K.T. , Norhawati Ahmad , Muammar Mohamad Isa , Musa F.A.S.

Nowadays, low power operational amplifiers (op-amp) are highly demand for most of the applications such as in medical and communication system. In this project, two stage op-amp is designed and operated at 1.8 V supply voltage. The supply voltage is scaled down to reduce the power dissipation of the op-amp. This is because the power will be high when there is a large supply voltage. The design is simulated and analysed using Mentor Graphic Pyxis software. This two stage op-amp is designed using the Silterra 0.13 μm process technology. The operational amplifier provides a Direct Current (DC) gain of 21.18 dB and a unity gain bandwidth of 6.31 MHz. The gain margin obtained from the op-amp is 14.07 dB and the phase margin of the op-amp is 94.26 ° for 3 pF compensation capacitor and 10 pF load capacitor. The result shows that circuit able to work at 1.8 V power supply voltage and the total power dissipation for the op-amp is 5.35 mW.

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Non-linear analysis of Self-Switching Diodes as microwave rectifiers

2017-01-01 , Shahrir Rizal Kasjoo , Zulfadhli Zailan , Sanna Taking , Wan Zuki Azman Wan Muhamad , Muammar Mohamad Isa , Arshad M.

A planar device known as the Self-Switching Diode (SSD) has been demonstrated as a high-speed rectifier, up to terahertz frequencies. The rectifying properties of SSD are dependent on a nonlinear current-voltage characteristic of the device. In this research, the rectification of two SSD rectifiers has been reported and their performances were evaluated. The observed results showed a good agreement with the nonlinear theoretical analysis of both rectifiers by means of a Taylor series which can be utilized in improving the rectifying performance of any diode-based rectifier specifically for diodes with tunable threshold voltage such as SSDs.

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Improved rectification performance and terahertz detection in hybrid structure of self-switching device (SSD) and planar barrier diode (PBD) using two-dimensional device simulation

2020-01-01 , Nor Farhani Zakaria , Shahrir Rizal Kasjoo , Muammar Mohamad Isa , Zarimawaty Zailan , Mohd Khairuddin Md Arshad , Song A.

Recently, simulations of In0.48Ga0.52As-based Planar Barrier Diode (PBD) and Self- Switching Device (SSD) as millimeter-wave rectifiers were reported. Both PBD and SSD have a planar structure, but with different insulating shapes and working principles. In this work, a hybrid structure of the reported PBD and SSD in a parallel configuration is proposed, to exploit the advantages of each device. The advantages of high rectifying properties in the SSD and fast switching rate of the PBD are combined in this hybrid structure in order to obtain an improved rectification performance at zero-bias in the near terahertz frequency region. Analysis of the curvature co-efficient, γ, which is defined as the ratio of the second order to the first order derivative of the device’s I-V function was performed to evaluate the rectification performance. AC transient analyses were then executed in various frequencies to imitate the high-frequency signal inputs. By using this hybrid structure, the highest value of γ achieved has been improved to ~19 V-1 at 70 mV, and ~6 V-1 at zero- bias (compared to the previous results on PBDs). The estimated cut-off frequency obtained was ~360 GHz (0.36 THz), operating at zero-bias.

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Silicon Self-Switching Diode (SSD) as a Full-Wave Bridge Rectifier in 5G networks frequencies

2022 , Tan Yi Liang , Nor Farhani Zakaria , Shahrir Rizal Kasjoo , Safizan Shaari , Muammar Mohamad Isa , Arun Kumar Singh , Mohd Khairuddin Md Arshad

The rapid growth of wireless technology has improved the network’s technology from 4G to 5G, with sub-6 GHz being the centre of attention as the primary communication spectrum band. To effectively benefit this exclusive network, the improvement in the mm-wave detection of this range is crucial. In this work, a silicon self-switching device (SSD) based full-wave bridge rectifier was proposed as a candidate for a usable RF-DC converter in this frequency range. SSD has a similar operation to a conventional pn junction diode, but with advantages in fabrication simplicity where it does not require doping and junctions. The optimized structure of the SSD was cascaded and arranged to create a functional full-wave bridge rectifier with a quadratic relationship between the input voltage and outputs current. AC transient analysis and theoretical calculation performed on the full-wave rectifier shows an estimated cut-off frequency at ~12 GHz, with calculated responsivity and noise equivalent power of 1956.72 V/W and 2.3753 pW/Hz1/2, respectively. These results show the capability of silicon SSD to function as a full-wave bridge rectifier and is a potential candidate for RF-DC conversion in the targeted 5G frequency band and can be exploited for future energy harvesting application.

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Review of mixer design for low voltage - Low power applications

2017-09-26 , Nurulain D. , Musa F.A.S. , Muammar Mohamad Isa , Norhawati Ahmad , Shahrir Rizal Kasjoo

A mixer is used in almost all radio frequency (RF) or microwave systems for frequency translation. Nowadays, the increase market demand encouraged the industry to deliver circuit designs to create proficient and convenient equipment with very low power (LP) consumption and low voltage (LV) supply in both digital and analogue circuits. This paper focused on different Complementary Metal Oxide Semiconductor (CMOS) design topologies for LV and LP mixer design. Floating Gate Metal Oxide Semiconductor (FGMOS) is an alternative technology to replace CMOS due to their high ability for LV and LP applications. FGMOS only required a few transistors per gate and can have a shift in threshold voltage (VTH) to increase the LP and LV performances as compared to CMOS, which makes an attractive option to replace CMOS.

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Comprehensive study on gate recess step for the fabrication of high-speed InGaAs/InAlAs/InP pHEMT

2017-01-03 , Muammar Mohamad Isa , Norhawati Ahmad , Siti Salwa Mat Isa , Muhammad Mahyiddin Ramli , Nazuhusna Khalid , Nurul Izza Mohd Nor , Shahrir Rizal Kasjoo , Missous M.

We report a comprehensive etching study on the gate recess step for the fabrication of the novel high speed pHEMT devices. The experiments focused on the elimination of 'hump' structure as a result of an incomplete etching process at the InGaAs cap layer. In this work, two types of test samples were used, namely bulk InGaAs and epitaxial structure together with an etch stop layer. The result showed that the etch rate of bulk InGaAs is about 360 A/min and the percentage of dome height is consistent at approximately 25%. Meanwhile, the study on pHEMT epitaxial layer showed that the etching time of 3 minutes is sufficient in order to completely remove the cap layer. Gate leakage current of magnitude more than 10 times lower is observed on the devices that engaging Succinic Acid as the gate recess etching agent. The optimized processing steps will tailor for highly reproducible pHEMT fabrication process for high speed applications.

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Low insertion loss of surface mount device low pass filter at 700 MHz

2019-06-01 , Khairi K.A. , Jamlos M.F. , Padmanathan S. , Mohd Aminudin Jamlos , Muammar Mohamad Isa

The paper involved with the design, simulation and fabrication of 6th order elliptical-based Surface Mount Device (SMD) LPF with cutoff frequency at 700 MHz. Fabricated LPF is consisted of four PCB layers which components of SMD are soldered on the top layer. Another three layers is for grounding and shielding, power supply and grounding void. The four layers is crucial to avoid interference between components. The research has find out that the momentum simulation is definitely required to improve the signals response compared to a normal simulation by ADS software. The comparison between momentum simulated versus measured and normal simulated versus measured is 0.2 dB and 29 dB correspondingly. Such huge difference leads to conclusion that momentum simulation is saving time without having much struggles and efforts to get optimum readings. The Proposed SMD LPF has a very low insertion loss of 0.965dB with a transition region of 195 MHz which is good steepness to avoid any image frequency.

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