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Dual-polarized flat rectenna for 2.45 GHz
(2013-01-01)
Phongcharoenpanich, C.
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Boonying, K.
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Kosulvit, S.
This paper presents the study and the design of the rectenna (antenna integrated with rectifying circuit) operating at the WLAN band of 2.45 GHz. The polarization diversity antenna fed by two linear electric probes is chosen for receiving RF power from the WLAN. The isolation of the proposed polarization diversity antenna is improved by inserting an annular rectangular-ring slot on the radiating plate. The obtained result of isolation the antenna is higher than 30 dB. The Experimental of the characteristics radiation patterns are obtained the cross polarization level lower than is 20 dB, a unidirectional beam and a maximum gain is higher than 7 dBi. The rectifying circuit is used voltage double diode with open stub matching circuit. The results of rectifying circuit found that the DC power is higher than 100 mV at -20 dBm. The measured results of the rectenna is the RF power to DC power conversion at the distance less than 1 m. © 2013 IEEE.
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Dual-band flat antenna for polarization diversity with high isolation
(2012-11-23)
Phongcharoenpanich, C.
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Boonying, K.
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Kosulvit, S.
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Laohapensaeng, T.
This paper presents the design of the dual-band flat antenna operating at 2.45 GHz and 5.25 GHz. This antenna is designed for polarization diversity of wireless LAN application (IEEE 802.11 a/b/g/n). The antenna is operated at dual-band with dual-polarization capability. The prototype flat antenna consists of a plate, a T-step slot, a rectangular slot, a rectangular ring strip, an air gap and a ground plane. The simulation process is done by using the CST Microwave Studio software. The results show the isolations higher than 15 dB that is satisfied the system requirement. The flat antenna is designed to obtain the unidirectional radiation pattern. The maximum gain is higher than 7 dBi. © 2012 IEEE.
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Polarization diversity unidirectional antenna for IEEE 802.11a applications
(2012-11-12)
Vongsack, S.
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Phongcharoenpanich, C.
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Kosulvit, S.
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Hamamoto, K.
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Wakabayashi, T.
The polarization diversity unidirectional antenna is proposed for IEEE 802.11a applications by using two-probe excited circular ring antenna above square reflector. The purpose of this investigation is to design a polarization diversity unidirectional antenna to resonate at the center frequency of 5.5 GHz to cover the frequency range from 5.2 to 5.8 GHz for wireless LAN system following IEEE 802.11a standard. The performances of the antenna such as the return loss, the isolation between two-probes, the radiation pattern and the gain, are analyzed by using Computer Simulation Technology (CST) Microwave Studio. The proposed antenna has a polarization diversity unidirectional pattern with maximum gain of 8.34 dBi. Moreover, the proposed antenna yields the front-to-back ratio better than 20 dB and the isolation between the two-probes better than 20 dB as well. Besides, the proposed antenna is useful for wireless local area network (WLAN) communication systems.
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A UWB bidirectional rectangular ring antenna fed by CDM with a rod and ridges for constant beam direction
(2012-07-16)
Vongsack, S.
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Lamultree, S.
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Osklang, P.
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Phongcharoenpanich, C.
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Kosulvit, S.
This paper presents an ultra-wideband (UWB) rectangular ring antenna excited by a circular disc monopole (CDM) with a conducting rod and two double ridges to radiate bidirectional pattern with constant beam direction along the entire UWB frequency range of 3.1-10.6GHz. The conducting rod and double ridges at the upper wall of the ring are added to solve the tilted beam problem at the higher edge frequency whereas the double ridges at the lower wall are used to enhance the impedance bandwidth. The dimensions of the rectangular ring and the CDM are initially considered to achieve the bidirectional pattern with the suitable resonant frequencies and bandwidth. Then, the parameters of copper rod and two double ridges are determined by parametric study using CST Microwave Studio simulation software. The prototype antenna was fabricated, and the measured results show good agreement with the simulated ones. The obtained bandwidth of |S <inf>11</inf>| < - 10 dB can cover the UWB frequency range as well as the bidirectional beam radiation with constant beam direction (θ = 0°, 180° and φ = 90°). The minimum and maximum measured gains are 3.1dBi to 5.3dBi, respectively. The proposed antenna possesses compact size with good radiation performance that can be a promising candidate for UWB applications. Copyright © 2012 S. Vongsack et al.
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Unidirectional antenna using two-probe excited circular ring above square reflector for polarization diversity with high isolation
(2012-01-01)
Vongsack, S.
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Phongcharoenpanich, C.
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Kosulvit, S.
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Hamamoto, K.
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Wakabayashi, T.
This paper presents a circular ring antenna fed by two perpendicular probes, both of which are placed above the square re°ector. The antenna is employed to radiate unidirectional beam for polarization diversity reception. A linear isolator is added to improve the isolation between the two probes. The antenna is proposed for the point-to-point communication of Wireless Local Area Network (WLAN) system according to the IEEE 802.11a standard in which the allocated frequency band ranges from 5.150 GHz to 5.825 GHz. The proposed antenna is compact and suitable for mass production. Without the dielectric material, the antenna is free of dielectric loss and capable of high power handling. The prototype antenna was fabricated and measured to verify the theoretical predictions. At the center frequency, the unidirectional pattern with the measured half-power beamwidths in two principal planes of 65 and 75 degrees is achieved. The front-to-back ratio is 31 dB, and the antenna gain is 7.42 dBi. The |S<inf>11</inf>| and |S<inf>21</inf>| are respectively -23:09 dB and -33:99 dB; the obtained bandwidth is 23.64%. Based on the aforementioned characteristics, the antenna is a potential candidate for polarization diversity of WLAN applications.
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UHF-RFID tag antenna using diamond structure and rectangular loop
(2011-08-12)
Pumpoung, T.
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Phongcharoenpanich, C.
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Kosulvit, S.
This paper proposes the UHF RFID tag antenna design for operation of the frequency band 920-925 MHz corresponding to the standard of UHF RFID in Thailand. The tag antenna fabrication from the thin FR4 substrate (ε<inf>r</inf> = 4.3) with the thickness of substrate of 0.25 mm. The pattern of the tag antenna is omni-directional one. The tag antenna design is used rectangular loop matching technique for matching between the tag antennas with IC chip with the impedance of 21.29-j191.7 Ω at the frequency of 922.5 MHz that is the center frequency. The meander line structure can be decrease the size of tag antenna to compact size. © 2011 IEEE.
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Analysis of radiation characteristics of a probe-excited rectangular ring antenna by the dyadic Green's function approach
(2009-01-01)
Lamultree, S.
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Phongcharoenpanich, C.
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Kosulvit, S.
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Krairiksh, M.
Radiation characteristics of a probe-excited rectangular ring antenna are investigated by using the dyadic Green's function approach. The radiation characteristics, such as radiation pattern, beam-peak direction, half-power beamwidth and directivity, are analyzed. For the specified operating frequency, the ring width and ring height are selected as the same cross-sectional dimension of rectangular waveguide operated at the dominant mode. The effects of the excited probe and rectangular ring to the modal distributions are described. For the desired modal distribution, the directivity primarily depends on the ring lengths. For compact size of the proposed antenna, the ring length of 0.4λ is chosen to provide a bidirectional pattern with the calculated half-power beamwidth in E-plane and H-plane of 100 and 69 degrees respectively, and directivity of 4.43 dBi. Furthermore, the prototype antenna was fabricated and measured. The coincided results between the theory and the experiment are obtained.
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Mutual information of mimo system in a corridor environment based on double directional channel measurement
(2009-01-01)
Keowsawat, P.
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Phongcharoenpanich, C.
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Kosulvit, S.
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Takada, J.
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Krairiksh, M.
Double directional channel measurements were made in a corridor environment with a channel sounder. A multidimensional high resolution algorithm was used to extract channel parameters for calculating the mutual information of a special Multiple-Input Multiple-Output (MIMO) system. This system utilized bidirectional dual-polarized antennas at both ends of the communication. In a corridor environment, the mutual information of this system was 12 b/s/Hz higher than that of the other MIMO system equipped with traditional 1λ horizontally-spaced vertically-polarized dipole array antennas. Depolarization of the vertical polarization transmission degraded the mutual information of the dipole array antennas in this environment. The angular spread of the incoming signals at the receiver ranged from 0.9° to 3.8° depending on the distance between the transmitter and the receiver. © 2009 J. of Electromagn. Waves and Appl. All right reserved.
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Two-probe excited circular ring antenna for MIMO application
(2009-01-01)
Krairiksh, M.
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Keowsawat, P.
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Phongcharoenpanich, C.
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Kosulvit, S.
This paper presents the analysis and design of a two-probe excited circular ring antenna. The analysis is conducted by using induced emf method and transmission line model. The design process is to choose a suitable radius of the ring for a single probe antenna. Then, the suitable probe length and ring length are determined for the two-probe antenna. Finally, isolation between the two probes is enhanced by insertion of an inductor coil between the probes. The operational characteristics of the prototype antenna at the frequency of 5.2GHz are measured and compared with calculation results. It is evident that these results are in good agreement. The antenna achieved isolation in excess of 20dB and VSWR less than 2: 1 over the desired bandwidth and a bidirectional radiation pattern with 4dBi gain. This antenna is suitable for Multiple-Input Multiple-Output (MIMO) system covering a long and narrow environment.
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Characteristics of an elliptical ring antenna excited by a linear electric probe
(2007-10-01)
Chawanonphithak, K.
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Phongcharoenpanich, C.
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Kosulvit, S.
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Krairiksh, M.
This paper presents the characteristics of an elliptical ring antenna excited by a linear electric probe. Based on the waveguide principle, the suitable cross-sectional dimension of the ring that yields the dominant mode (TEC11 mode) will be formulated in terms of the cut off wavelength. The variation of the antenna characteristics, depending on cross-sectional dimension, ring length and probe length, were investigated using numerical electromagnetic code (NEC) based on the method of moments (MoM). From the experiment, the prototype antenna provides bidirectional pattern with HPBW in E-plane and H-plane of 83 and 46 degrees, respectively, and the gain of 5.1 dBi with SWR 2:1 over the bandwidth of 14% for the operating frequency of 1.92 GHz. This antenna is applicable for mobile communication on a highway, on a street, in a corridor and in a tunnel with the advantages of simple configuration and low cost.

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