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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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Improvement microstrip patch antenna for ultra-wideband by C-shaped wide slot
(2010-12-01)
Satthamsakul, S.
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Puntheeranurak, S.
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Benjankaprasert, C.
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Anantrasirichai, N.
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Wakabayashi, T.
The simple rectangular patch antenna is designed at frequency 7 GHz and matched impedance with 50 ohms of transmission line. The technique to achieved widest bandwidth from 3 GHz to 12 GHz coverage standard of UWB applications is proposed by etches out slot on the ground plane with inset technique. The configuration and the size of slot on the ground plane are important to enhanced bandwidth, and inset feed is used for good impedance matching in wide frequency range. The radiation patterns of each frequency show the bi-directional with null at angle ±90°. ©ICROS.
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Design of right angle slot antenna for dual band and dual polarized with wireless network
(2010-12-01)
Pomsathit, A.
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Benjangkaprasert, C.
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Anantrasirichai, N.
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Rakluea, Paitoon
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Wakabayashi, T.
A novel compact and light weight antenna for dual band and dual polarized right angle slot antenna fed by micorstrip line use in wireless network technology is designed. The antenna composed of three right angle slot radiators on a same ground plane. Two right angle slots in the same size are arranged for circularly polarized at frequency 4.95 GHz and the other one is designed for linearly polarized at frequency 2.45 GHz. Therefore, in order to achieve dual band and dual polarized with good matching, the technique of arrangement is recommended. The simulation results of return loss, VSWR, gain, axial ratio, and radiation patterns are shown at resonant frequency 2.45 GHz and 4.95 GHz. ©ICROS.
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Compact ultra-wideband antenna with dual band-notch design using several parasitic elements
(2010-01-01)
Kueathaweekun, W.
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Benjangkaprasert, C.
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Anantrasirichai, N.
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Wakabayashi, T.
A compact ultra-wideband (UWB) antenna with band-notches designed using a technique that incorporates several parasitic elements is presented. The proposed antenna can be applied to UWB communication systems to avoid interference with other wireless communication systems. By using parasitic elements (C-shaped, inverse C-shaped, L-shaped, J-shaped, and line strip) inserted in the slot antenna, desired bands can be rejected, such as Wireless Local Area Networks (WLAN), (5-6 GHz) and Worldwide Interoperability for Microwave Access (WiMAX), (3.5 GHz). The characteristics of the antenna can be modified to tune the band-notch frequency and the bandwidth of the band-notch. Several parasitic elements can be used to create a dual band-notched design. A UWB slot antenna and four types of single band-notched design are also provided for reference. The paper also presents experimental results regarding the input performance, radiation patterns, and gain of the antenna at different operational frequencies.
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Compact slot antenna with rectangular-ring tuning stub for ultra-wideband application
(2009-01-01)
Kueathaweekun, W.
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Anantrasirichai, N.
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Benjangkaprasert, C.
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Wakabayashi, T.
A compact microstrip-fed slot antenna with rectangular-ring tuning stub for ultra-wideband application is presented. The characteristics of antenna are proposed and analyzed for instance return loss, bandwidth, and far field radiation patterns. The measurement results of the impedance matching for the proposed antenna show the impedance bandwidth of 120% of the center band (3.09-12.15GHz), determined by -10 dB return loss. The measured radiation patterns are bi-directional and average gain is 3.5 dBi.
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Wide-band slot antenna fed by coplanar waveguide for WLAN applications
(2009-01-01)
Kueathaweekun, W.
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Puntheeranurak, S.
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Benjangkaprasert, C.
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Anantrasirichai, N.
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Wakabayashi, T.
This paper presents the slot antenna fed by coplanar waveguide (CPW) for WLAN applications. The characteristics of an antenna are proposed and analyzed for instance return loss, bandwidth and far field radiation patterns. Simulation results of the proposed antenna show the impedance bandwidth, determined by-10 dB return loss, approximate 140 % (1.66-9.44GHz) of the center band. The radiation patterns are bi-directional, and maximum gain is 5.7 dBi at 5.0 GHz. The simulation results of the slot antenna are analyzed by using IE3D Software.
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Compact CPW-Fed wide slot antenna for ultra-wideband applications
(2009-01-01)
Kueathaweekun, W.
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Purahong, B.
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Benjangkaprasert, C.
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Anantrasirichai, N.
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Wakabayashi, T.
A compact ultra-wideband (UWB) CPW-fed slot antenna design is presented. The antenna consists of a wide rectangular slot on the ground plane with rectangular-ring shaped tuning stub. The simulation result of the impedance matching for the proposed antenna show the impedance bandwidth, determined by-10 dB return loss of 116 %, coverage 2.94 GHz to 11.06 GHz for UWB applications. The simulation radiation patterns and gain of the antenna at different operational frequencies are presented and discussed.
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Gain and radiation improvement technique for rectangular patch antenna
(2009-01-01)
Satthamsakul, S.
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Puntheeranurak, S.
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Benjankaprasert, C.
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Anantrasirichai, N.
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Wakabayashi, T.
This paper proposed the techniques for improved gain and radiation patterns include bandwidth enhancement of patch antenna by cutting slots in the ground plane. We proposed three styles of slot cut in the ground plane. There are narrow slot, wide slot, and wide slot with conductor strips. Each style is shown the gain improvement with wideband use in X-band communication systems. Finally, the gain is 6.96 dBi at frequency 10.5 GHz and the average gain from 8 to 10.5 GHz is 4.97 dBi. The radiation pattern shown the low back lobe with good directivity.

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