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    Characteristics of a dual-broadband antenna with crossed elliptical probes and L-shaped slits
    (2017-12-19)
    Khoomwong, Ekajit
    ;
    Phongcharoenpanich, Chuwong
    Characteristics of a dual broadband antenna are investigated. The antenna consists of crossed elliptical probes, L-shaped slits, and split circular ground-planes. The proposed antenna covers various widely-employed frequency standards: IEEE 802.11b/g/n, IEEE 802.16, GSM, UMTS and LTE. The design and investigation are based on numerical simulations. The dual broad-bandwidths are 1.46 GHz (1.69-3.15 GHz) and 1.69 GHz (4.93-6.62 GHz), which simultaneously cover the above-mentioned frequency standards. The radiation patterns are of conical-beam type with peak gains of 3.1 and 5.1 dBi at 2.45 and 5.5 GHz, respectively. It has the advantage of main-beam directions pointing to nearly the same tilt angle for both main operating bands, which can be very useful for ceiling-mounted installations and simultaneous dual-band operations.
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    Dual-band thin printed microwave absorber
    (2016-09-06)
    Khoomwong, Ekajit
    ;
    Santaluna, Samran
    ;
    Phongcharoenpanich, Chuwong
    A dual-band thin printed-circuit-board (PCB) microwave absorber is proposed for applications in 2.4 and 5 GHz frequency bands. Each unit cell of the absorber utilized a simple combination of a square ring and a thick cross-dipole with some additional tuning elements. In the design process, numerical simulations were performed first for optimal characteristics, and then a prototype absorber was created successfully by simple print-transferring and etching processes. The measured absorption bandwidth (50%) of 170 MHz (2.36-2.53 GHz) and 830 MHz (5.09-5.92 GHz) are achieved for the first and second band, respectively, with the wideband feature at the second operating band. The absorption at the center frequencies of bands, 2.45 and 5.5 GHz, are also found feasible at 97.85% and 97.76%, respectively. From the experiments, the proposed absorber was suitable for many applications requiring absorptions in the 2.4/5GHz bands as desired. The measured results were agreed well with ones from the simulations. The advantages of the proposed absorber are thin, simple and low-cost structure that can be useful for cost-effective applications.
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    Bidirectional ring antenna fed by a superellipse surface probe for 2.4/5GHz WLAN applications
    (2016-09-06)
    Khoomwong, Ekajit
    ;
    Innok, Apinya
    ;
    Phongcharoenpanich, Chuwong
    This paper presents the design of a dual-band bidirectional ring antenna fed by a superellipse surface probe for 2.4/5GHz WLAN applications. The Method of Moments (MoM) with RWG basis function was utilized in the study and design processes. A prototype antenna was fabricated successfully with the advantages of simple and low-cost structure. The measured impedance bandwidth of 810 MHz (2.10-2.91 GHz) and 2.39 GHz (3.57-5.96 GHz) are achieved for the first and second band, respectively. The peak-gains are also feasible, 4.67 dBi at 2.45 GHz and 7.83 dBi at 5.5 GHz, with bidirectional radiation patterns for both bands. From the experimental field tests, the proposed antenna was suitable for most applications in long and narrow communication sites in 2.4/5GHz bands as desired. Also, the measured and calculated results were in good agreement.
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    Dual-band conical-beam antenna using 3D monopole with symmetrical slot on the ground plane
    (2011-11-07)
    Phongcharoenpanich, C.
    ;
    Khoomwong, E.
    In this paper, the utilization of a conducting spherical monopole radiator as a dual-band conical-beam antenna is investigated. The multi-band property is achieved by adding a quarter-wavelength slot (stub) and a conducting cylindrical ring for matching and bandwidth enhancement of the second operating band. The design is investigated and summarized based on numerical experiments or simulations. It is found that the proposed antenna provides a conical-beam with the impedance bandwidths (S11 less than 10 dB) covering two bands of operating frequencies, 2.4 to 2.5 GHz and 5.15 to 5.825 GHz. The best-matched values of S11 are about 21 and 16 dB for the first and second operating bands, respectively. Gains of the antenna are reasonably applicable, about 3.1 and 7.1 dBi at the centers of the two operating bands above. The far-field radiation patterns are of conical-beam type as required, with the main beams directed at the same 45-degree elevation angle for both operating bands. A prototype antenna has been successfully fabricated and most of the experimental results are agreed well with ones from the simulations. The investigation of this antenna also guides us that a quarter-wavelength slot may be further applied for other multi-band applications. © 2011 IEEE.
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    Dual-band conical-beam antenna for IEEE 802.11 a/b/g applications
    (2010-12-01)
    Phongcharoenpanich, C.
    ;
    Khoomwong, E.
    In this paper, the utilization of a conducting spherical monopole radiator as a dual-band conical-beam antenna is investigated. The multi-band property is achieved by adding a quarter-wavelength slot (stub) and a conducting cylindrical ring for matching and bandwidth enhancement of the second operating band. The design is investigated and summarized based on numerical experiments or simulations. It is found that the proposed antenna provides a conical-beam with the impedance bandwidths (S11 less than -10 dB) covering two bands of operating frequencies, 2.4 to 2.5 GHz and 5.15 to 5.825 GHz. The best-matched values of S11 are about -21 and -16 dB for the first and second operating bands, respectively. Gains of the antenna are reasonably applicable, about 3.1 and 7.1 dBi at the centers of the two operating bands above. The far-field radiation patterns are of conical-beam type as required, with the main beams directed at the same 45-degree elevation angle for both operating bands. A prototype antenna has been successfully fabricated and most of the experimental results are agreed well with ones from the simulations. The investigation of this antenna also guides us that a quarter-wavelength slot may be further applied for other multi-band applications. © 2010 IEICE Institute of Electronics Informati.