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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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Physicochemical factors related to 'Monthong' durian fruit maturity
(2018-08-30)
Youryon, P.
;
Rattanaphon, J.
;
Supapvanich, S.
;
Krairiksh, M.
Heterogeneous maturation of durian fruit on the market is a main problem. The aim of this work was to investigate certain factors related to the maturity of 'Monthong' durian fruit. The durian fruit at immature, onset of maturation, onset of ripening, ripe and full ripe stages were harvested. Non-destructive factors such as specific gravity and total soluble solids (TSS) content of peduncle and destructive factors such as cut-fruit visual appearance, pulp dry weight, colour, TSS content and carotenoids content were monitored. Both specific gravity and TSS content of peduncle were increased until the onset of ripening stage and then remained constant during ripening. The visual appearance showed the increase in pulp yellowness and space between pulp and peel which positively changed with the maturation increase. The pulp dry weight and b* value were increased whilst L* value was decreased as the ripening increased. The pulp TSS concentration was dramatically increased until full ripe and then remained constant. Carotenoids content of the pulp was also obviously increased from immature to the onset of ripening stage and it then remained constant. In conclusion, the decrease in specific gravity and increase in peduncle TSS concentration could be non-destructive factors indicating durian fruit ripening.
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Analysis of a Sensor using Rician k-factor for Identification of a Spherical Conductor Submerged in Soil
(2018-07-02)
Yoiyod, P.
;
Pathoumvanh, S.
;
Phongcharoenpanich, C.
;
Krairiksh, M.
The Unexploded Ordnance (UXO) problem is a barrier plaguing for the country's development since the UXO contamination can render lands unusable. The UXO is defined as a metallic material submerged into the soil. Generally, the clearance team uses a handheld metal detector for scanning sub-surface and sensing the location of such a bomb. This outdated method is labor intensive and time consuming when scanning in the large area. Hence, the high-speed and lightweight scanning system for sensing underground object is desired. This paper investigated a feasibility to develop a Ground Penetrating Radar (GPR) system that can detect metallic bombs which is submerged in soil at the depth of 30 cm from the surface. The scattered waves from an object were calculated at different positions and the Rician k-factor was estimated from the ratio of mean to variance. The position with highest k-factor indicates the location of the target UXO.
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A switch-beam circular array antenna using pattern reconfigurable Yagi-Uda antenna for space communications
(2017-12-19)
Ngamjanyaporn, P.
;
Kittiyanpunya, C.
;
Krairiksh, M.
This paper presents a switch-beam circular array antenna using pattern reconfigurable Yagi-Uda antenna. A two-beam switching Yagi-Uda antenna is applied as an array element. The 3-element circular array is introduced to be able to switch the main beam in azimuth direction by switching the beam and shifting the excitation phase of array elements. The array antenna is designed at 2.4 GHz for drone or UAV radio controlling. The two-beam elements and 90°-shifted phase of excitation are applied to realize the proposed switched-beam array antenna. The simulated results show that the array antenna can provide 7 main beam directions covering a half azimuth plane (0° ≤ φ ≤ 180°) and gain of the array antenna is higher than 7 dBi.
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Detecting granulated fruit by measuring dual-frequency back scattered waves
(2017-07-02)
Kittiyanpunya, C.
;
Phongcharoenpanich, C.
;
Krairiksh, M.
Granulation is a kind of defection in fruits that must be non-destructively detected. Electromagnetic wave measurement is a feasible technique for in-situ measurement. With thick peel, it is necessary to eliminate the effect of peel so that sole effect of variation of pulp can be detected. This paper presents the simulated scattering coefficient from fruit with dual-frequency that exhibits more obvious results than the single-frequency measurement. The results lead to the appropriate design of a sensor for granulation detection.
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Analysis of a sensor for fruit classification using Rician k-factor in a continuous process
(2017-01-12)
Leekul, P.
;
Krairiksh, M.
This paper presents simulation results that describes feature of a sensor system in a continuous process. The Rician k-factors from a single frequency-monostatic and a wideband-bistatic measurements can be used as indicators for classifying maturity stage of durian fruits.
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A reflectometer using antenna mixers
(2016-03-07)
Inrun, R.
;
Vichianchai, R.
;
Leekul, P.
;
Kittiyanpunya, C.
;
Krairiksh, M.
This paper presents a sensor for monitoring moisture content of paper. The reflection coefficient of paper at various moisture contents are measured and used for determining humidity of paper. The resultant IF output of 50 MHz from the reflectometer operating at the frequency of 2.40 GHz and 2.45 GHz shows an obvious difference in reflection coefficient for dry and wet paper depicting the feasibility to design a moisture content sensor.
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Microwave sensor for defected fruit classification
(2016-03-07)
Leekul, P.
;
Chivapreecha, S.
;
Krairiksh, M.
This paper presents a microwave sensor operating at the frequency of 2.45 GHz that can detect defected fruits. In this work, orange is used as an example. Granulation of orange is detected by measuring mean and standard deviation of the magnitudes of S-parameters of the orange at different positions. From the simulated S-parameters of patch antennas surrounding the fruits, it was found that the reflected signal from the fruit and the coupled signal to the antenna oriented perpendicular to the fruits provide the obvious variation and can be used as indicators for justification. This cost effective sensor is a good candidate for fruit classification.
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Pattern and frequency reconfigurable meander line Yagi-Uda antenna
(2016-01-20)
Utayo, M.
;
Sangthongngam, W.
;
Kittiyanpunya, C.
;
Krairiksh, M.
This paper presents a pattern and frequency reconfigurable meander line Yagi-Uda antenna for digital terrestrial television reception. To achieve a compact size for installing on a vehicle, the antenna is designed with meander line. The main beam switching and resonant frequency tuning are accomplished by loading two driven elements and four parasitic elements with the short or open of RF switches. The frequency is reconfigured with different electrical length of the driven element. The direction of the beam is shifted by alternating the short or open status of RF switches in parasitic elements.
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Dual beam Yagi patch antenna
(2015-10-22)
Samree, S.
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Getjulom, S.
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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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