Mohamed Razman Yahya
Universiti Putra Malaysia
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Featured researches published by Mohamed Razman Yahya.
international rf and microwave conference | 2006
Nor Fazlina Mohd Lazim; Zaiki Awang; Sukreen Hana Herman; Uzer Mohd Nor; Mohd Nizam Osman; Ashaari Yusof; Asban Dollah; Mohamed Razman Yahya; Abdul Fatah Awang Mat
This paper reports on the use of thin lead zirconate titanate (PZT) films for monolithic microwave integrated circuit (MMIC) capacitors to replace existing materials for better size-reduction. The films were sputtered on Pt/Ti/SiO2 coated, undoped silicon wafers. Square Pt electrodes with sides ranging from 10 mum to 50 mum were patterned on the PZT layers to form the capacitors. Results of this study show that PZT thin films can be utilized for efficient size reduction in MMIC. The linewidth obtained for a 50 Omega transmission line is merely 300 nm - this results in a size reduction of approximately five times compared to conventional MMIC. For a 50 times 50 mum electrode area, capacitance values ranging from 5 to 20 pF were obtained at frequencies up to 20 GHz. Suitable de-embedding of S parameters using Cascade microwave probes revealed films with relative permittivities of the order of 100 to 500
ieee international conference on semiconductor electronics | 2006
Mohd Khairy Othman; Asban Dolah; Nurul Afzan Omar; Mohamed Razman Yahya
This paper report a statistical method of performing wafer lapping experimental using design of experiment (DOE) technique in order to get best lapping time to reduced thickness of GaAs wafer. Lapping speed, lapping time, oscillator speed and weight was selected as four main factor determine the shortest time of thickness reduction. A complete 2 4 factorial of 4 factors (16 run) was design to determined the effect of selected factor. The lapping process was carried out using ULTRATEC Lapping& Polishing machine while the wafer thickness was characterized using Logitech non contact gauge. It was found that best lapping parameter was using lapping speed at 3 r.p.m, oscillator speed at 2 r.p.m and 3 weight block for duration of 240 sec. This parameter is able to reduce 156 mum of wafer within 240 second without any crack problems and able to give good reference of reduction of GaAs wafer thickness process period.
ieee international rf and microwave conference | 2008
Zulkifli Ambak; Rosidah Alias; Azmi Ibrahim; Sabrina Mohd Shapee; Mohd Zulfadli; Mohammed Yusoff; Muhammad Redzuan Saad; Mohamed Razman Yahya; Abdul Fatah Awang Mat
This paper presents a top-down design of the microstrip coupled line Band pass filter (BPF) embedded in low temperature co-fired ceramic (LTCC) for 5 GHz wireless LAN applications. It includes the design, simulation, fabrication and measurements. The filter circuit was designed and simulated based on Agilent Advanced Automation (ADS2005A) software. Then, the physical dimensions of components and the filter itself is subsequently determined and the physical design is later performed in the layout window of Empire XcCEL. All measured simulations are analyzed and compared to design specifications and characteristics (curve fitting). Any inaccuracy is taken into account where corrected design is further recovered.
asia-pacific conference on applied electromagnetics | 2007
Zulkifli Ambak; Rosidah Alias; Azmi Ibrahim; Sabrina Mohd Shapee; Samsiah Ahmad; Mohamed Razman Yahya; Abdul Fatah Awang Mat
This paper described the Low Technology Co-fired Ceramic (LTCC) design methodology at TMRND based on FDTD EM simulations that are required when designing the RF/microwave circuit. In this paper, 3D EM analysis and optimization with Finite Different Time Domain (FDTD) software Empire XcCeltrade from IMST was applied to achieve accurate modeling of the RF/microwave circuit using LTCC technology. A multilayer spiral inductor was selected for discussion to show this LTCC design technique. The main elements of the LTCC design technique relies on three important guidelines; use accurate component models, link the circuit schematic to the layout to reduce errors and finally link the layout to an EM simulator to detect coupling problems.
international rf and microwave conference | 2006
Syamsuri Yaakob; W. R. Wan Abdullah; Mohd Nizam Osman; A. K. Zamzuri; Romli Mohamad; Mohamed Razman Yahya; A. F. Awang Mat; M. R. Mokhtar; H. A. Abdul Rashid
Third order intermodulation (IM3) can cause non-linearity effects which result in interference and crosstalk between the subcarriers in radio over fibre (ROF) transmissions. This paper presents the experimental results of the effect of varying the magnitude of the laser bias current on the IM3 in an ROF system with direct modulation. We also investigate the behaviour of the system spurious free dynamic range (SFDR) with the bias current variation. The results show that there will be an optimum bias current range for a given range of the radio frequency (RF) input power in order to minimise the IM3 effect and obtain the best possible SFDR for the system
ieee international conference on semiconductor electronics | 2006
Syamsuri Yaakob; Mohd Azmi Ismail; Romli Mohamad; Mohamed Razman Yahya; Abd. Fatah Awang Mat; M. R. Mokhtar; Hairul Azhar Abdul Rashid
This paper presents the evaluation of radio over fibre (ROF) capability with electroabsorption modulator (EAM) as a downlink photodetector (PD) and uplink radio frequency (RF) modulator. The results show that the EAM device has potential to be adopted as the transceiver at the remote antenna unit (RAU) for the system. The 130 m ROF system with biased EAM is capable to obtain a symmetrical WLAN 802.11a data rate of 18 Mbps with laser diode output power of 8.7 dBm.
ieee international conference on semiconductor electronics | 2004
L.H. Guan; M.S. Jusoh; Asban Dolah; A. Yusof; Mohamed Razman Yahya; B.Y. Majlis
The etching selectivity of AlGaAs and InGaAs was studied and analyzed. Different chemical solutions and compositions were varied to study the etch rate effect between these two materials. The etching rates and selectivity of the H/sub 3/PO/sub 4/:H/sub 2/O/sub 2/:H/sub 2/O, H/sub 2/SO/sub 4/:H/sub 2/O/sub 2/:H/sub 2/O and C/sub 6/H/sub 8/O/sub 7/:H/sub 2/O/sub 2/ is compared. The results show that the C/sub 6/H/sub 8/O/sub 7/:H/sub 2/O/sub 2/ chemical solution exhibits higher etch rate and significant selectivity in comparison with H/sub 3/PO/sub 4/:H/sub 2/O/sub 2/:H/sub 2/O, H/sub 2/SO/sub 4/:H/sub 2/O/sub 2/:H/sub 2/O.
international conference on electronic design | 2008
R. Sanusi; Mohd Azmi Ismail; K. Norhapizin; A. I. Abdul Rahim; Arjuna Marzuki; Mohamed Razman Yahya
In this paper, very low loss and high isolation single pole double throw (SPDT) switch design for microwave applications using pseudomorphic high-electron mobility transistor (pHEMT) is presented. The MMIC switch design is developed using a commercially available 0.15 mum GaAs pHEMT technology. At the operating frequency of 15 GHz, the SPDT switch has 1.89 dB insertion loss and 26.66 dB of isolation. It also demonstrates 28.8 dBm of input P1dB gain compression point (P1dB) and 25.9 dBm of output P1dB.
international conference on electronic design | 2008
Muhammad Redzuan Saad; Zulkifli Ambak; Rosidah Alias; Azmi Ibrahim; Sabrina Mohd Shapee; Mohd Zulfadli Mohammed Yusoff; Mohamed Razman Yahya; Abdul Fatah Awang Mat
A top-down detail design of a 5 GHz micro strip coupled line band pass filter in LTCC is presented in this paper. LTCC, which stands for low temperature co-fired ceramic is especially used for wireless and high-frequency applications. Now, the importance of LTCC is becoming more prominent in views of the fact a lot organizations has been funding R&D-projects regarding this new technology that focuses on larger implementation of functionality in LTCC substrates. Although Malaysia is new to this technology, its industry has certainly high hopes on the LTCC innovation to make a breakthrough and contribute significant benefits to the technology, industry, market and also, the country itself. The filter circuit was designed and simulated by using ADS2005A. Then, the physical dimensions of components and the filter itself is subsequently determined and the physical design is later performed in the layout window of Empire XcCEL. All measured simulations are analyzed and compared to design specifications and characteristics (curve fitting). Any inaccuracy is taken into account where corrected design is further recovered.
ieee region 10 conference | 2008
Amiza Rasmi; Arjuna Marzuki; M.A. Ismail; Ahmad Ismat Abdul Rahim; Mohamed Razman Yahya; Abdul Fatah Awang Mat
This paper presents the design and fabrication of two-stage medium power amplifier (MPA) using 0.5 mum GaAs PHEMT technology for the wireless LAN applications. The die size of this amplifier is only 1.7 mm times 0.85 mm. At a supply voltage of 5.0 V and 5.8 GHz operating frequency, a 2-stage MPA achieves a linear gain (S21) of 16.39 dB, P1 dB of 20.18 dBm, power gain of 15.15 dB and the PAE of 25.29%.