Krairiksh, Monai

Preferred name

Krairiksh, Monai

Alternative Name

Krairiksh', Monai

Krairiksh, M.

Main Affiliation

School of Engineering

monai.kr@kmitl.ac.th

Now showing 1 - 10 of 74

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Electromagnetic wave scattering on 2D PEC cylinders using complex source point techniques and uniform geometrical theory of diffraction
(2010-07-30)
Lertwiriyaprapa, T.
;
Phaebua, K.
;
Phongcharoenpanich, C.
;
Krairiksh, M.
An analysis of the path loss in the durian orchard is presented by using the complex source point technique (CSP) and the uniform geometrical theory of diffraction (UTD). The 2D Gaussian beams (GBs) expansion scattered by 2D cylindrical structures are presented. The GB can be generated by using the CSP. The GBs expansion can provides an efficient way of the synthesis of the radiation pattern of the antenna. The cylindrical structures are preliminarily assumed to be a perfect electric conductor (PEC). The source (square patch antenna) is located on a durian. The CST-program uses to simulate the source pattern including the effect of durian for the UTD calculation. The CSP-UTD is applied to analyze the scattered fields from the cylindrical structures. The multi-path propagation and the path loss prediction in various aspects are then obtained. Also, the exact solution of the CSP scattered by a cylindrical is used to compare the UTD results. The good agreements are obtained in this work.
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Beam-Scanning Reflectometer for Detecting Granulated Fruits
(2017-03-01)
Kittiyanpunya, Chainarong
;
Leekul, Prapan
;
Phongcharoenpanich, Chuwong
;
Krairiksh, Monai
The problem of granulation in fruits costs vendors a big chunk of their revenue, hence a non-destructive sensor that can identify granulated fruits without destroying good fruits is highly desirable. This paper presents such a sensor system based on beam-scanning reflectometer operating at 2.45 GHz. Beams of scattered waves from several directions around the fruit are reflected by a conical reflector and scanned by a phased array of pattern reconfigurable Yagi-Uda antennas equipped with 1-b phase shifters for lowest loss in feed network. The collected data are used to calculate the Rician k-factor. The system was tested with plasticine spheres and real tangerines. It was found that the system with an eight-beam array was better than one with a four-beam array. This system may prove useful for quality control of tangerines and other agricultural products.
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A sensor for fruit classification using doppler radar
(2018-11-09)
Leekul, P.
;
Krairiksh, M.
This paper presents a microwave sensor that can detect defected fruits. In this work, mangosteen is used as an example. Translucent is detected by measuring Doppler frequency as mangosteen is rotated. From the simulated scattered waves at different directions around the fruits, the different in scattered wave results in Doppler signal from the defected fruit. The different D.C. voltage from the mixer identified whether there is translucent for the whole fruit. This cost effective sensor is a good candidate for fruit classification.
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Multiband Antenna for RF Energy Harvesting
(2018-07-02)
Nguyen, Ngan
;
Tuan, Ninh Nguyen
;
Nguyen, Quoc Cuong
;
Truong, Vu Bang Giang
;
Krairiksh, Monai
This paper presents a multi resonant bow-tie slot antenna for Rectifying Antenna in Ambient RF Energy Harvesting (RFEH). The proposed antenna operates at five frequencies 0.9 GHz, 1.8 GHz, 2.1 GHz, 2.45 GHz and 5.8 GHz corresponding with ambient RF sources in our environment bychanging the position and size of the air gap on the traditional bow-tie antenna as well as bow-tie antenna. A good agreement is observed between the simulation and measurement results. The proposedantenna is suitable for high efficiency RF energy harvesting system.
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President's message
(2011-12-01)
Krairiksh, Monai
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Resolution Improvement in Preharvest Sensor
(2019-10-01)
Dao, Hoang Nam
;
Krairiksh, Monai
This work illustrates the benefit of subtracted beam antenna we presented earlier for a sensor system in fruit pre-harvesting. The angular resolution pattern of a receiving antenna that shows how far the unwanted object (fruit) can be eliminated from the desired target (fruit under test) is proposed. The link budget for the beam subtracted antenna is also calculated to indicate the transmitting power for ensuring the receiving power for a normal sensitivity of the sensor. This calculation shows that the beam subtracted antenna can be employed in pre-harvesting of fruits.
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Dual beam Yagi patch antenna
(2015-10-22)
Samree, S.
;
Getjulom, S.
;
Teangrod, S.
;
Kittiyanpunya, C.
;
Krairiksh, M.
This paper presents a dual beam Yagi patch antenna. The antenna operates in the ISM band of 2.41 and 2.45 GHz. It consists of rectangular patch fed at two different probe positions. The patch has two reflectors each provides directional pattern in two perpendicular directions. The isolation is better than 20 dB and directivity is more than 3 dBi. This antenna can be applied for receiving video signals from wireless cameras.
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Analysis and design of a Gaussian backscatter antenna with ring focus feed
(2010-12-01)
Thaiwirot, W.
;
Wongsan, Rangsan
;
Krairiksh, M.
This paper presents analysis and design of a Gaussian backscatter antenna with ring focus feed. The curvature of main reflector is Gaussian, and the subreflector is a portion of an ellipse. The antenna has axial symmetry. A backscattering technique is used with the main reflector to achieve wide beamwidth. The input parameters of the proposed antenna are derived in closed form. Physical theory of diffraction (PTD) is used to analyze the radiation pattern of the proposed antenna and verified with experimental results. The effects of the support structures on the radiation patterns of the proposed antenna have been investigated experimentally. The proposed antenna can produces high gain and wide beamwidth (coverage angle θ = ±65°). This antenna can be used for realizing earth coverage beam in LEO satellite or indoor wireless LAN applications.
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A multiband CPW-Fed slot antenna with fractal stub and parasitic line
(2012-12-28)
Hongnara, Tanan
;
Mahattanajatuphat, Chatree
;
Akkaraekthalin, Prayoot
;
Krairiksh, Monai
This paper presents a multiband CPW-fed slot antenna with fractal stub and parasitic line. The conventional wideband slot antenna with fractal stub is modified by inserting the parasitic line surrounding the fractal stub that affects the attribution to be a multiband operation suitable for some applications in wireless communication systems. The parasitic line surrounding the fractal stub can generate a dual-notched frequency that can be controlled by varying the parameters of the parasitic structure. The lengths of slit and stub on both sides of the parasitic line can control the lower and higher notched frequencies, respectively. Additionally, the prototype of the proposed antenna can operate and cover the applications of DCS 1800, WiMAX IEEE 802.16, WLAN IEEE 802.11a/b/g, and IMT advance systems.
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Measurement of Radiated Field from Transmitting Antennas Located in Various Environments
(2019-04-01)
Krairiksh, Monai
;
Kittiyanpunya, Chainarong
;
Limpiti, Thunyawat
;
Tantisopharak, Tanawut
;
Leekul, Prapan
In microcellular communications, the transmitting antennas can be installed at low heights above the ground. However, even for low elevation towers, installation cost is still high. One of the possible ways for the deployment of base station antennas is to install them near the ground in order to do away with the tower. The main purpose of this paper is to suggest installation of the radiating antennas near the ground and tilting their orientation toward the sky - a totally nonintuitive solution. It will be shown that such deployments have the potential of reducing slow fading and can further enhance the signal strength close to the radiating antenna. This paper provides measured data for the received fields to validate the theoretical conjecture of such a deployment in various environments. The measured results are presented for 245, 800, 1000, and 2400 MHz. It is illustrated that such an unorthodox deployment can result in a low cost for the installation of base station antenna as the towers are not necessary. This can be useful in restoring communications in emergency situations where minimum infrastructure exists.

Krairiksh, Monai

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