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Measurement of Radiated Field from Transmitting Antennas Located in Various Environments
(2019-04-01)
Krairiksh, Monai
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Kittiyanpunya, Chainarong
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Limpiti, Thunyawat
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Tantisopharak, Tanawut
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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.
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Applications of Electromagnetic Waves to the Quality Control of Agricultural Products
(2018-12-10)
Tantisopharak, Tanawut
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Krairiksh, Monai
Electromagnetic waves have long been applied in wide area of applications. Recently, it has been increasingly interested in the agricultural applications. Since the object interacts the electromagnetic waves proportional to its properties, it can be used to identify and distinguish the quality of the agricultural products. This paper discusses some recent techniques to control the quality of several agricultural products.
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Nondestructive Determination of the Maturity of the Durian Fruit in the Frequency Domain Using the Change in the Natural Frequency
(2016-05-01)
Tantisopharak, Tanawut
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Moon, Hongsik
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Youryon, Pannipa
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Bunya-Athichart, Kanokpon
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Krairiksh, Monai
This paper proposes a nondestructive technique to determine the stages of maturity of durian fruits. The presented methodology utilizes the electromagnetic scattering properties from the fruits over time for identification of the stage of maturity using its natural frequencies. Both simulation and experimental results show that the natural frequencies in the scattering responses change with the maturity of the durian fruit. Particularly, the change in the fundamental resonant frequency is used as a possible identification criterion for characterization of the stage of maturity. This is because the dielectric constant of the core of the fruit changes with its degree of maturity. In addition, the experimental results indicate that the variation of the dominant resonant frequency of durian fruits varies at different stages of maturity and this has the potential to be applied as a criterion to identify the stages of maturity.
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Investigation of the natural resonant frequencies of palmyrah palm juice for quality control
(2016-03-07)
Tantisopharak, Tanawut
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Keowsawat, Panisa
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Kanahna, Rachen
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Krairiksh, Monai
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Sarkar, Tapan K.
This paper proposes an identification methodology to distinguish between pure and adulterated palmyrah palm juice. The resonance behavior of the palmyrah palm juice has been investigated through numerical electromagnetic simulation. From the scattered response, the natural frequencies of the palmyrah palm juice are extracted. The identification can be performed by cataloging and comparing these pre computed library of the natural resonant frequencies associated with the standard palmyrah palm juice to check for the quality of the samples to be tested.
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Identification of maturity of fruit in the frequency domain using its natural frequencies
(2012-11-26)
Tantisopharak, Tanawut
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Krairiksh, Monai
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Moon, Hongsik
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Lee, Woojin
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Sarkar, Tapan
This paper presents an identification methodology to determine the stage of maturity of a fruit by using its natural resonant frequencies, which can be extracted from its scattering response. Since the dielectric properties of a fruit are determined by its chemical properties, the identification can be performed by comparing the libraries of poles to determine the stage of maturity for that fruit. © 2012 IEEE.
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Adaptive array antenna using on-off and CMA algorithms for microwave RFID readers
(2011-01-01)
Tantisopharak, Tanawut
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Boonpoonga, Akkarat
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Phongcharoenpanich, Chuwong
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Sirisuk, Phaophak
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Krairiksh, Monai
This paper proposes an adaptive antenna using a combination of on-off and CMA algorithms. With the proposed technique, the on-off algorithm is first employed to search for a desired signal direction in which maximum received power is achieved. Then, interference is suppressed by performing CMA. Simulations are conducted according to the potential application of the proposed adaptive antenna. The simulation results show the SINR improvement implying that the proposed adaptive antenna can be applied to microwave RFID systems in order to resolve reader collision. Furthermore, the proposed adaptive antenna is implemented and then experimented. The experimental results verify that the proposed adaptive antenna can reduce interference resulting in the collision problem. Copyright © 2011 The Institute of Electronics, Information and Communication Engineers.
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Wordlength effect on CMA adaptive antenna with digital beam synthesis initialization
(2008-12-01)
Boonpoonga, Akkarat
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Tantisopharak, Tanawut
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Sirisuk, Phaophak
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Krairiksh, Monai
This paper investigates the wordlength effect on the CMA adaptive antenna with digital beam synthesis initialization. The antenna is a four-element circular array whose main beam can be switched into different directions by using digital beam synthesizer. A beam obtained from digital beam synthesis is exploited as an initial beam for CMA. A weight vector for generating initial beams of CMA is chosen by determining radiation patterns. The SINR of the digital beam synthesis-based CMA adaptive antenna with different wordlengths are shown. Moreover, the step-size constant of CMA is also investigated and properly chosen to avoid underflow and overflow phenomena. © 2008 IEEE.
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Parallel multistage CM array with constrained initialization of digital beam synthesis
(2008-12-01)
Boonpoonga, Akkarat
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Tantisopharak, Tanawut
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Sirisuk, Phaophak
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Krairiksh, Monai
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Simple initialization scheme for CMA adaptive antenna by using digital beam synthesis
(2008-10-06)
Tantisopharak, Tanawut
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Boonpoonga, Akkarat
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Sirisuk, Phaophak
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Krairiksh, Monai
This paper presents a simple technique of initialization for CMA adaptive antenna. The technique utilizes digital beam synthesis for a circular array antenna to synthesize the beams in digital domain. The synthesized beam can be switched into different directions by choosing proper weight vectors. The weight vectors are calculated through a phased array principle. The beams obtained from the synthesis are employed to initial CMA in order to improve its convergence property. The technique makes the compact adaptive antenna using CMA possible. Simulation results show that the proposed technique can significantly improve the convergence property of CMA. ©2008 IEEE.
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A dual-band dual-feed switched-beam patch antenna for WLAN application
(2008-01-01)
Tagapanij, Jukkrit
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Sooksumrarn, Pobsook
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Tantisopharak, Tanawut
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Janin, Suwan
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Krairiksh, Monai
Due to the demand of dual-band modern wireless communications, this paper presents a dual-band patch antenna for IEEE802.11 a and g wireless local area network (WLAN) system. The antenna has bidirectional patterns that can be switched by an RF switch to select the feeding probe positions. The 2.4 GHz and 5.2 GHz patches are stacked on a ground plane and are matched to the RF switch by open stubs. Analysis and design are illustrated and throughput improvement is demonstrated in an indoor environment. Copyright © 2008 The Institute of Electronics, Information and Communication Engineers.

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