Chutchavong, Vanvisa

Preferred name

Alternative Name

Chutchavong, V.

Main Affiliation

School of Engineering

vanvisa.ch@kmitl.ac.th

Now showing 1 - 9 of 9

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Ultra-wideband slot antenna on flexible substrate for WLAN/WiMAX/UWB Applications
(2014-01-01)
Archevapanich, Tuanjai
;
Lertwatechakul, Mayuree
;
Rakluea, Paitoon
;
Anantrasirichai, Noppin
;
Chutchavong, Vanvisa
An ultra-wideband slot antenna on flexible substrate is designed to support a wide range of wireless communication systems. The antenna is a rectangular slot antenna fed by microstrip line with conductor strip and tuning stub on flexible substrate (Mylar Polyester film). The rectangular slot is etched out from the ground plane with conductor strip in the slot, and the other plane contains a microstrip line with tuning stub. The proposed antenna’s effective frequency range covers overall standard bands of WLAN, WiMAX, and UWB. The antenna was simulated and analyzed by using IE3D Zeland software [1]. And the simulation results presents the characteristics of the antenna in terms of bandwidth return loss, VSWR, and radiation patterns.
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Lifespan Estimation of Closed-Circuit Television (CCTV) Systems Using Weibull Modeling
(2026-02-01)
Chutchavong, Vanvisa
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Pirajnanchai, Virote
;
Doungpan, Satawat
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Kasettakarn, Witchapon
;
Phungtua-eng, Thanapol
Ensuring the availability and reliability of electronic components or materials during operation necessitates conducting a sampling inspection of their lifespan. This is particularly crucial when comparing equipment or materials deployed in various areas with diverse environments, conditions, and situations. Many studies rely on one-method parameter estimation methods, which fall short in identifying the two explicit parameters of the Weibull distribution. Moreover, inaccurate parameter estimation methods impede the attainment of reliable analysis results. Consequently, this paper introduces three analytical estimation methods to determine the parameters of the Weibull distribution. The accuracy of these methods is evaluated using the mean square error (MSE). Furthermore, we utlized the Kolmogorov–Smirnov and Anderson–Darling test on real datasets, confirming that the data follow a Weibull distribution. Simulation results indicate that the maximum likelihood estimate outperforms the other estimators by minimizing the MSE and yielding optimal parameters. These optimal parameters were then applied to real CCTV datasets, demonstrating a good fit and enabling assessment of CCTV lifespan through the mean time to failure, which is estimated to be 6.6 years. This holds true even when the equipment operates in environments with different conditions and situations.
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Optimized Gaussian Pulse Design for UWB System Using Particle Swarm Optimization Based-on Generalized Bessel Polynomials
(2022-01-01)
Chutchavong, Vanvisa
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Anuwongpinit, Thanavit
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Purahong, Boonchana
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Archevapanich, Tuanjai
;
Janchitrapongvej, Kanok
The ultrawideband system operates a very short pulse with enormous bandwidth to provide high data rates for data transmission. To design the UWB pulse, considering the pulse shape is very necessary, and a spectral emission mask of the designed pulse should meet the FCC spectral mask requirement between frequency range 3.1 GHz to 10.6 GHz. The traditional UWB pulse design is based on the Gaussian derivative. However, the frequency spectrum is not satisfied the FCC spectral mask requirement. In this study, the Gaussian pulse can be designed from the mathematical characteristic of the generalized Bessel polynomial. The spectral efficiency of the proposed pulse can be improved by the combination of the derivative of Gaussian pulse with a weight coefficient optimization with particle swarm optimization (PSO). PSO is a population-based optimization algorithm inspired by animal behavior. PSO is applied with generalized Bessel polynomial transfer function to gain the best weight coefficient, we proposed to optimize its weight vector to design a pulse that exceeds to FCC spectral mask. The results were found in MATLAB software show that generalized Bessel polynomials can approximate the proposed pulse with combination method and PSO. The spectral efficiency is improved to 89.30% and the spectrum is greater close to the FCC spectral mask requirement. To confirm an improved spectral efficiency compared to the previous works.
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Hybrid facial features with application in person identification
(2020-08-14)
Purahong, Boonchana
;
Chutchavong, Vanvisa
;
Aoyama, Hisayuki
;
Pintavirooj, Chuchart
This paper presents the hybrid facial feature with identification and verification based on facial images. A query facial image had been taken under different conditions of the facial image of the same person (as the query). The query facial image database was constructed. We have used the technique of three-dimensional (3D) Dlib facial landmarks using a direct linear transform technique. A set of absolute affine invariance had been constructed from a series of the 3D landmark quadruplets, which make the facial identification robust to affine geometric transformation. These 3D facial features serve as a coarse feature depending on each individual facial structure. The construct of the 2D detail features represents the edge facial image confined between the 2D Dlib landmarks. The similarity of the 2D feature is achieved by aligning the 2D query edge image against that of the reference edge image. The geometric transformation matrix is estimated from the 2D Dlib landmarks, where correspondence is well established. An identification/verification cost function using a combination of local 2D facial features and global 3D facial features is utilized to verify and identify a query facial image against a candidate facial image(s). The performance of the algorithm yielding an area of 99.97% perfect classification is represented as a value under the receiver operating characteristic (ROC) curve.
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Luminance-chrominance gain equalizer based on bernstein polynomials
(2010-01-01)
Chutchavong, Vanvisa
;
Sangaroon, Ornlarp
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Benjangkaprasert, Chawalit
;
Janchitrapongvej, Kanok
This paper presents a linear luminance-chrominance gain equalizer for correcting the linear chrominance gain distortion in the color TV transmission system. The proposed gain equalizer was implemented based on Bernstein polynomials. As it is known that the Bernstein filter has flexible parameters to adjust the circuit performance for the best results. In addition, the modulated 20T sine-squared pulse test signal is generated for testing the performance of the proposed gain equalizer, which can be measured all three types of the linear chrominance distortions. As the results, the proposed gain equalizer is also proved to be efficient in equalizing both the low gain and the high gain chrominance distortions without degrading its phase characteristics. © 2010 The Institute of Electrical Engineers of Japan.
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A triple-band high-gain planar dipole with double interdigital structure for indoor LTE and WLAN base stations
(2019-02-01)
Archevapanich, Tuanjai
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Chomtong, Pongsathorn
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Chutchavong, Vanvisa
;
Akkaraekthalin, Prayoot
This paper presents a triple-band antenna using interdigital technique based on dipole structure at a frequency of 1.8 GHz. Using this technique, harmonic frequency bands can be generated as desired, resulting in the resonance frequencies of the second and third harmonics at 2.4 and 5.2 GHz, respectively. The proposed antenna consists of two square brass plates with an overall size of 63 × 64 mm2. The antenna bandwidths are found to be 410 MHz (1.59–2.00 GHz), 70 MHz (2.40–2.47 GHz), and 790 MHz (4.99–5.78 GHz), and the gains obtained are 9.63, 8.95, and 8.97 dB, respectively. The radiation patterns are directional at all frequency bands. Therefore, the proposed antenna can be appropriately used for indoor long-term evolution (LTE) and wireless local area network (WLAN) base stations. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
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A triple band antenna using dipole and interdigital structures
(2018-06-01)
Archevapanich, Tuanjai
;
Chomtong, Pongsathorn
;
Chutchavong, Vanvisa
;
Akkaraekthalin, Prayoot
This paper proposes a triple band antenna using interdigital technique based on a planar dipole structure. The antenna has been designed at the fundamental frequency of 1.8 GHz. With this proposed technique, the harmonic frequency bands of 2.45 and 5.2 can be created. The designed antenna can support various applications including indoor LTE, WLAN and wireless sensor base station systems. The simulation results of the antenna show superior characteristics in form of return loss and radiation pattern.
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Rectangular slot antenna with Asymmetrical conductor strip for bandwidth enhancement coverage UWB standard
(2014-01-01)
Archevapanich, Tuanjai
;
Rakluea, Paitoon
;
Anantrasirichai, Noppin
;
Purahong, Boonchana
;
Chutchavong, Vanvisa
This paper presents the bandwidth enhancement of rectangular slot antenna fed by microstrip line on the flexible Mylar Polyester film substrate. Asymmetrical conductor strip is designed and inserted in the rectangular slot to extend the bandwidth from 3.06 GHz to 7.2 GHz frequency range. Besides, the rectangular conductor at the end of the feeding microstrip line is introduced for increasing the bandwidth at high frequency up to 12.32 GHz. This improved antenna to cover standard frequency range of UWB (3.1 GHz – 10.6 GHz). Finally, as to reject the frequency band of IEEE 802.11a (5.15 GHz – 5.35 GHz), the line strip at the side of tuning stub is added. In this case, the band-notched frequency from 5.15GHz to 5.38 GHz can be easily obtained.
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A Flexible and Compact UWB MIMO Antenna with Dual-Band-Notched Double U-Shaped Slot on Mylar® Polyester Film
(2025-09-01)
Chutchavong, Vanvisa
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Chanwattanapong, Wanchalerm
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Wongsin, Norakamon
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Rakluea, Paitoon
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Tangjitjetsada, Maleeya
Ultra-wideband (UWB) technology is a crucial facilitator for high-data-rate wireless communication due to its extensive frequency spectrum and low power consumption. Simultaneously, multiple-input multiple-output (MIMO) systems have garnered considerable attention owing to their capability to enhance channel capacity and link dependability. This article discusses the development of small, high-performance MIMO UWB antennas with mutual suppression capabilities to fully use the benefits of both technologies. Additionally, the suggested antenna features a straightforward design and dual-band-notched characteristics. The antenna structure includes two radiating elements measuring 85 × 45 mm2. These elements use a rectangular patch provided by a coplanar waveguide (CPW). Double U-shaped slots are incorporated into the rectangular patch to introduce dual-band-notched properties, which help mitigate interference from WiMAX and WLAN communication systems. The antenna is fabricated on a Mylar® polyester film substrate of 0.3 mm in thickness, with a dielectric constant of 3.2. According to the measurement results, the suggested antenna functions efficiently across the frequency spectrum of 2.29 to 20 GHz, with excellent impedance matching throughout the bandwidth. Furthermore, it provides dual-band-notched coverage at 3.08–3.8 GHz for WiMAX and 4.98–5.89 GHz for WLAN. The antenna exhibits impressive performance, including favorable radiation attributes, consistent gain, and little mutual coupling (less than −20 dB). Additionally, the envelope correlation coefficient (ECC) is extremely low (ECC < 0.01) across the working bandwidth, which indicates excellent UWB MIMO performance. This paper offers an appropriate design methodology for future flexible and compact UWB MIMO systems that can serve as interference-resilient antennas for next-generation wireless applications.

Chutchavong, Vanvisa

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