Tuntrakool, Sunti

Preferred name

Tuntrakool, Sunti

Alternative Name

Tuntrakool, S.

Main Affiliation

School of Industrial Education and Technology

sunti.tu@kmitl.ac.th

Now showing 1 - 10 of 11

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Quadrature oscillator with independent frequency control using ECCIIs
(2015-01-26)
Kumngern, Montree
;
Tuntrakool, Sunti
This paper presents a new mixed-mode quadrature oscillator. The proposed structure employs two electronically tunable second-generation current conveyors, two grounded capacitors and three grounded resistors which is suitable for integrated circuit implementation. Unlike previously oscillators, both the condition of oscillation and the frequency of oscillation of the proposed oscillator can be controlled using resistors and/or current-gain of ECCII. The circuit provides two quadrature current outputs and two quadrature voltage outputs. The current output terminals also possess high-impedance level which can be directly connected to the next stage without additional buffer circuits. PSPICE simulation results are given to confirm the workability of the proposed structure.
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A new quadrature sinusoidal oscillator for telecommunication system using VDDDAs
(2016-03-22)
Chaichana, Amornchai
;
Jaikla, Winai
;
Suwanjan, Peerawut
;
Tuntrakool, Sunti
A CMOS voltage differencing differential difference amplifiers (VDDDAs) based voltage-mode quadrature sinusoidal oscillator is proposed. The proposed oscillator is based on the two integrator loop configuration with amplifier wherein the frequency of oscillation (FO) is tuned by the time constant of two integrator and the condition of oscillation (CO) is tuned by gain of amplifier. It is constructed from two VDDDAs, two resistors, and two grounded capacitors. With this structure, it is attractive to develop in monolithic chip. The tuning of frequency of oscillation can be electronically done without affecting the condition of oscillation. Also, the condition of oscillation can be adjusted by external resistor without affecting to frequency of oscillation. The simulation results have been demonstrated and discussed using parameters of 0.18um TSMC CMOS technology and +0.9V power supply voltages.
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Broadband Reflective Metasurface at X-band Frequency Using Snowflakes Fractal Ring Design
(2025-01-01)
Yaziz, Nur Syahirah Mohd
;
Rahim, Mohamad Kamal A.
;
Samsuri, Noor Asmawati
;
Zubir, Farid
;
Tuntrakool, Sunti
A broadband reflective metasurface has been designed to integrate inward and outward fractal Koch rings operating at X-band frequencies. The integration between the inward and outward fractal Koch ring creates the snowflake fractal shape that operates at a center frequency of 10 GHz. Based on the simulated results, the reflection values are 0.9 with the reflection phase of 1800 which is between 900 to -900. Overall, all resonance frequencies exhibit more than 90% reflected power, with bandwidth of 1.90 GHz that cover from 8.70 GHz to 10.60 GHz.
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Temperature Insensitive Current-Mode Four Quadrant Multiplier Using Single CFCTA
(2017-02-09)
Tuntrakool, Sunti
;
Suwanjan, Peerawut
;
Jaikla, Winai
A four quadrant multiplier of two current input signals using active building block, namely current follower cascaded transconductance amplifier (CFCTA) is presented in this paper. The proposed multiplier consists of only single CFCTA without the use of any passive element. The presented circuit has low impedance at current input node and high impedance at current output node which is convenient for cascading in current mode circuit without the need of current buffer circuits. The output current can multiply two input currents with temperature insensitivity. Moreover, the magnitude of output current can be controlled electronically via DC bias current. With only single active building block, the presented multiplier is suitable for integrated circuit implementation for analog signal processing. Simulation results from a PSpice program are presented in order to demonstrate the multiplier proposed here.
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Geometry-Driven Performance of Unit Cells in Multiband Reflective Metasurfaces: A Comparative Study
(2025-01-01)
Taufiqqurrachman
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Rahim, Mohamad Kamal B.A.
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Samsuri, Noor Asmawati Binti
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Wijayanto, Yusuf Nur
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Yaziz, Nur Syahirah Mohd
A multiband reflective metasurface can be designed using a multi-ring resonator, where the resonator can take various shapes such as circular, square, hexagonal, triangular, and others. This paper presents a comparative study of unit-cell multiband reflective metasurfaces based on their geometric structure, focusing on reflection magnitude, reflection phase, and bandwidth performance of hexagonal and triangular shapes. Both proposed designs are designed and simulated at X-band frequencies using an F4BMX220 substrate with a thickness of 1.5 mm. Simulation results show that the hexagonal shape offers better reflection performance and a wider bandwidth compared to the triangular shape.
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Multiband Reflective Metasurface at X-Band Frequency Using Multi-Square Ring Resonators (SRRs)
(2025-01-01)
Taufiqqurrachman
;
Rahim, Mohamad Kamal B.A.
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Asmawati Binti Samsuri, Noor
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Wijayanto, Yusuf Nur
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Syahirah Mohd Yaziz, Nur
A multiband reflective metasurface has been designed using a multi-Square Ring Resonator (SRR) operating at X-band frequencies. Each SRR is designed to resonate at 8, 10, and 12 GHz, respectively. Based on the simulated results, the reflection values are -0.4 dB at 8 GHz, -1.86 dB at 10 GHz, and -1.99 dB at 12 GHz, while the reflection phases are -1.06° at 8 GHz, -9.8° at 10 GHz, and -1.98° at 12 GHz. Overall, all resonance frequencies exhibit more than 60% reflected power, with bandwidths of 0.67 GHz at 8 GHz and 0.2 GHz at 10 and 12 GHz.
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Single DVCCTA based voltage-mode quadrature sinusoidal oscillator with electronic controllability
(2014-01-01)
Tuntrakool, Sunti
;
Jaikla, Winai
;
Suwanjan, Peerawut
This paper presents simple voltage-mode quadrature sinusoidal oscillator. The proposed oscillator consists of one differential voltage current conveyor Tran conductance amplifier (DVCCTA), one electronic resistor (constructing from two NMOS transistors), and two grounded capacitors. The frequency of oscillation (FO) and condition of oscillation (CO) can be electronically tuned via external bias current which is easily controlled by microcontroller. The PSPICE simulation results using parameters of 0.25us TSMC CMOS technology are included and found that with 10MHz frequency of oscillation, the total harmonic distortions (THDs) for VO1 and VO2 are about 0.643% and 0.489%, respectively. The power consumption is nearly 3.1 mW at ±1.25V power supply voltages. With simple construction, the proposed oscillator is convenient to develop in monolithic chip.
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Voltage Differencing Current Conveyor Differential Input Transconductance Amplifier: Novel Active Element and Its Resistorless Filtering Application
(2019-10-01)
Sotner, Roman
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Jerabek, Jan
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Langhammer, Lukas
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Petrzela, Jiri
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Jaikla, Winai
This paper introduces novel modification of active element based on current conveyor transconductance amplifier core abbreviated as current controlled voltage differencing current conveyor differential input transconductance amplifier (CC-VDCCDITA). The active element is implemented by recently developed and manufactured IC modular device based on I3T25 0.35 μm ON Semiconductor CMOS process. Active element uses three internal active cells of this IC device for construction of the CC-VDCCDITA. An application example of proposed element in simple special resistor-less electronically adjustable biquadratic filter is shown. Brief comparison with state-of-the-art solutions indicates beneficial features of proposed solution. Simulation results in Cadence IC tool accompany precise laboratory experimental measurements with real prototype.
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A Model of Engineering Education for Innovation
(2018-09-17)
Sunthonkanokpong, Wisuit
;
Murphy, Elizabeth
;
Tuntrakool, Sunti
The purpose of this paper is to present implications of innovation for Engineering Education (EE) and research. The specific objectives are as follows: Analyze innovation policies from India, Malaysia, Thailand, Korea and the Association of South-East Nations (ASEAN): Identify common themes between policies; determine implications for EE for Innovation (EEFI); create a model of EEFI; determine implications for EEFI research. Analysis of the policies led to the identification of seven themes: prosperity, humanity, inclusivity, capacity, sustainability, inquiry, and community. These themes guided the creation of a model of EEFI. The model consists of four principal bases: learner-based; STEM + AE-based, problem-based and; project-based. Learner-based focuses on what engineers are in terms of their personal and professional competencies. STEM + AE are a reminder that engineers must be more than technicians, well-versed in STEM. Their education needs to include the arts and entrepreneurship. The problem base refers to EEFI activity being driven by complex, authentic, ill-structured challenges, problems and issues that have a social as well as a technical character. The project-base involves collaborative efforts to find answers to questions and create solutions to problems and challenges. Implications for research highlight a range of approaches to researching EEFI from quantitative surveys of perceptions of participants to complex research designs whereby engineers in training are collaboratively solving real problems in communities.
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Comparison between Snowflake Fractal and Koch Fractal for Intelligent Reflecting Surface
(2025-01-01)
Yaziz, Nur Syahirah Mohd
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Rahim, Mohamad Kamal A.
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Samsuri, Noor Asmawati
;
Zubir, Farid
;
Tuntrakool, Sunti
This paper compares two fractal metasurface designs for Intelligent Reflecting Surfaces at X-band which is with a snowflake-shaped fractal ring and a fractal Koch metasurface. The snowflake ring design with a 10GHz center frequency achieves very high reflectance (~90%) at resonance and a bandwidth of about 1.90 GHz. The Koch-fractal design response with a bandwidth of 2.10 GHz at a center frequency of 10GHz. The method for both fractal metasurfaces and a comparable on their reflection coefficients, phase behaviour, bandwidth and current distributions are discussed in section II and section III.

Tuntrakool, Sunti

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