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Author: search.filters.author.Chawanonphithak, Krittaya

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    5.8 GHz notched UWB bidirectional elliptical ring antenna excited by circular monopole with curved slot
    (2007-12-01)
    Chawanonphithak, Krittaya
    ;
    Phongcharoenpanich, Chuwong
    ;
    Kosulvit, Sompol
    ;
    Krairiksh, Monai
    This paper presents a UWB bidirectional elliptical ring antenna excited by circular monopole with curved slot for 5.8 GHz band rejection. High Q operation of band notch is obtained in the simulation. The characteristics of the antenna have many attractive features in both technically and economically, such as bidirectional radiation pattern, wide impedance bandwidth, moderate gain, small size, low cost, and easy fabrication. The antenna is desired for application in conventional narrow and long path service area, where some frequency bands pre-occupied by the WLAN standard IEEE 802.11a.
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    An ultra-wideband bidirectional antenna with modified circular disc monopole excited elliptical ring
    (2007-08-28)
    Chawanonphithak, Krittaya
    ;
    Phongcharoenpanich, Chuwong
    ;
    Kosulvit, Sompol
    ;
    Krairiksh, Monai
    The antenna design for ultra-wideband (UWB) signal radiation is one of the main challenges of the UWB system, especially when the antenna can satisfy the requirement of low-cost, compactness, linear polarization and bidirectional pattern. This paper proposes a UWB bidirectional antenna with introducing the ψ shape feeder to circular disc monopole (CDM) excited elliptical ring for modern base station in UWB system. The simulation results are presented UWB performance of this antenna by using Computer Simulation Technology (CST®). The return loss of better than 10 dB covers the frequency range from 3 to 25 GHz, directivity at the direction toward θ=0° and 180° from 2.8 dBi at 3 GHz to 4.6 dBi at 11 GHz. The proposed antenna can achieve bidirectional pattern over the bandwidth of 7.5 GHz. The bidirectional radiation pattern is desirable for many applications in long and narrow path service cell. ©2007 IEEE.
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    NEC simulation of a bidirectional antenna using a probe excited elliptical ring
    (2005-12-01)
    Chawanonphithak, Krittaya
    ;
    Phongcharoenpanich, Chuwong
    ;
    Krairiksh, Monai
    This paper describes the characteristics of a bidirectional antenna using a probe excited elliptical ring. Based on the waveguide principle, a design of elliptical ring cross section that yields the propagation in dominant mode can be chosen and clarified by Numerical Electromagnetic Code (NEC). The quarter wavelength probe can accomplish matching condition. Subsequently, a decision of the ring length that obtains the desired directivity as well as the efficient radiation pattern, standing wave ratio (SWR), polarization, and bandwidth can be found by simulation. To investigate the characteristics of the proposed antenna for applying at the base stations, the wired grid model must be constructed. Using NEC simulation, the antenna characteristics can be carried out. The antenna prototype is fabricated and tested to verify the validity of our design method and the usefulness in Thai Mobile system operated at the center frequency of 1.92 GHz, The proposed antenna radiating bidirectional beam is suitable for narrow and long path service area with simple configuration and cost effective. © 2005 IEEE.
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    Electromagnetic coupling of a probe inside elliptical ring
    (2005-01-01)
    Chawanonphithak, Krittaya
    ;
    Phongcharoenpanich, Chuwong
    ;
    Kosulvit, Sompol
    ;
    Krairiksh, Monai
    The so-called dyadic Green function technique is used to accomplish the electromagnetic coupling of a probe inside elliptical ring. The mode distribution is clarified. The attenuation of the field along the ring is investigated. From the results of the analysis, it will be utilized as equivalent electric and magnetic current source at an aperture of a probe excited elliptical ring to determine far field radiation. © 2005 IEEE.