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A dual-wideband crossed elliptical disc antenna with reconfigurable radiation patterns for multiband applications
(2020-01-01)
Khoomwong, Ekajit
;
Phongcharoenpanich, Chuwong
This paper presents the design of a crossed elliptical disc antenna with two broad operating bandwidths, which covers several widely-employed frequency standards: IEEE 802.11b/g/n (WLAN), IEEE 802.16 (WiMAX), GSM/UMTS and LTE The antenna comprises a crossed elliptical radiator, step-fed transitions, L-shaped slits and split (defected) circular ground-planes. Moreover, the antenna is equipped with four switches to have reconfigurable options for the conical-beam radiation patterns. The fabricated antenna prototype offers the dual broad-bandwidths of 1.17 GHz (1.88-3.05 GHz) and 2.05 GHz (4.67-6.72 GHz), which cover the required frequency bands. The peak gains of the normal-mode conical beams are 3.05 and 5.91 dBi at 2.45 GHz and 5.5 GHz, respectively. It has the advantage of having main-beam directions pointing to nearly the same tilted angle for both operating frequencies, which is very useful for most simultaneous dual-band operations and ceiling-mounted installations.
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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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Multi-frequency printed microwave absorber with adjacent absorption peaks by dual-layer technique
(2017-12-19)
Khoomwong, Ekajit
;
Phongcharoenpanich, Chuwong
A multi-frequency printed microwave absorber with very close absorption peaks is designed using a dual-layer technique. The absorption ranges are applicable in the lower WiMAX bands with the adjacent bands (i.e. 2.3/2.7GHz), and also covering almost all U-NII-1/2/3 bands. The absorber consists of two layers with simple rectangular copper patterns, which can improve the modeling and manufacturing accuracy. The design processes are based on numerical simulations. The results show three absorption bands with bandwidths (at 50%) of 140MHz (2.27-2.41GHz), 130MHz (2.68-2.81GHz) and 740MHz (5.025.76GHz). The absorption peaks in each band (i.e. at 2.35, 2.75 and 5.45GHz) are at 98.7%, 85.0% and 99.5%, respectively. The presented absorber exhibits fairly wide-angle characteristics of wave incidence. The advantages of the proposed absorber are thin, simple and low-cost with adjacent absorption peaks, which is suitable for various applications in the lower-band WiMAX and the U-NII frequency ranges, simultaneously.
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Design of ultra-broadband bidirectional ring antenna with superellipse slot using MoM-RWG
(2017-12-19)
Khoomwong, Ekajit
;
Phongcharoenpanich, Chuwong
This paper presents a very simple bidirectional ultra-broadband antenna, which comprises a cylindrical ring, a disc surface probe, and a superellipse slot. The proposed antenna covers many world-famous frequency bands: GSM, UMTS, LTE, WLAN, WiMAX and UWB. In the design, numerical simulations are performed using the method of moments (MoM) with RWG basis function. The ultra-broad bandwidth is approximately 9.2 GHz (1.71-10.91 GHz). The radiation patterns are bidirectional with feasible peak gains for the entire band. The antenna has the advantages of very simple structure for manufacture and ultra-broadband for bidirectional applications, which is a suitable candidate for long and narrow communication sites.
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Simple and Low-Cost Dual-Band Printed Microwave Absorber for 2.4-and 5-GHz-Band Applications
(2017-10-26)
Khoomwong, Ekajit
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Phongcharoenpanich, Chuwong
In this research, a dual-band thin printed-circuit-board (PCB) microwave absorber has been proposed for applications in 2.4 and 5 GHz frequency bands. Each unit cell of the absorber consists of a square ring and a thick cross-dipole, augmented with the tuning elements. In the design process, numerical simulations were performed for the optimal characteristics of the absorber and an absorber prototype was fabricated using the simple print-Transferring and etching process. The measured absorption bandwidths (50 %) of 170 MHz (2.36-2.53 GHz) and 830 MHz (5.09-5.92 GHz) were achieved for the first and second bands, respectively, with the wideband characteristic at the second operating band. The absorption rates near the center frequencies (2.45 and 5.5 GHz) were respectively 97.85 % and 97.76 %. The simulation and measured results are in good agreement. Furthermore, the incidence-Angle dependencies of the absorber were of moderately wide angles with the absorption capacity of at least 50 % for both operating bands. The proposed absorber is suitable for a variety of applications requiring absorption in the 2.4/5 GHz bands.
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Dual-band thin printed microwave absorber
(2016-09-06)
Khoomwong, Ekajit
;
Santaluna, Samran
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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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Design of a Dual-Band Bidirectional Antenna Using Superellipse-Monopole-Fed Rectangular Ring for IEEE 802.11 a/b/g/n Applications
(2016-01-01)
Khoomwong, Ekajit
;
Phongcharoenpanich, Chuwong
This paper presents the design of a dual-band bidirectional ring antenna fed by a superellipse surface probe for 2.4/5 GHz 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) is 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 2.4/5 GHz bands as desired. Also, the measured and calculated results were in good agreement.
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Analysis of an arbitrarily rotated slot on a conducting spherical cavity
(2007-12-01)
Khoomwong, Ekajit
;
Phongcharoenpanich, Chuwong
The formulation for analyzing an arbitrarily rotated rectangular slot antenna at arbitrary location on a conducting spherical cavity is considered by using the technique of dyadic Green's function. The convergence tests of solutions and some radiation characteristics are investigated for various cases when the physical parameters, such as slot orientations and wide range of cavity sizes, are changed.
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Radiation characteristics of a vertically rectangular slot at arbitrary location on conducting spherical cavity
(2006-12-01)
Khoomwong, Ekajit
;
Phongcharoenpanich, Chuwong
This paper presents the dyadic Green's function approach for analyzing a vertical-aligned rectangular slot antenna which can be located at arbitrary latitude on a conducting spherical cavity. Some investigations on characteristics of the antenna, such as radiation patterns, are considered. The characteristics of the antenna are also pointed out when the slot length and cavity size are changed. Finally, numerical results of the derived dyadic Green's function approach are compared with that of the classical vector potential approach. © 2006 IEEE.

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