Browsing by Author "Ke, Qing-Xiang"

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A circular CPW-fed slot antenna resonated by the circular loop for broadband circularly polarized radiation
(2008-05-01)
Deng, I-Chung
;
Ke, Qing-Xiang
;
Lin, Ren-Jie
;
King, Yueh-Tsu
;
電子工程學系及電子研究所
The coplanar waveguide (CPW) fed circular slot antenna, resonated by the circular loop with a narrow opening, is designed for obtaining broadband circularly polarized (CP) radiation. The length of protruded signal strip (L-S) is utilized to adjust the phase difference between two orthogonal field components in the circularly polarized waves. In this design, the proposed antenna has the minimum return loss of -56.5 dB at the frequency of 2.403 GHz. The impedance and 3 dB axial-ratio bandwidths can reach up to 740 MHz or 33.3% and 390 MHz or 16.6%, respectively. In addition, the simulated results are about as good as those of the measured ones. (C) 2008 Wiley Periodicals, Inc.
A novel design of a CPW-fed single square-loop antenna for circular polarization
(2008-09-01)
Deng, I-Chung
;
Lin, Ren-Jie
;
Ke, Qing-Xiang
;
Huang, Jia-Min
;
Chang, Kow-Ming
The experimental and simulated results for the proposed antenna are investigated in this article. Moreover, a novel broadband design of a circularly polarized (CP) single square slot antenna fed by a single coplanar waveguide is presented. By appropriately choosing the circumference of the square-loop, the length of the protruded strip, and the gap, this proposed antenna thus owns good CP radiation and good impedance match simultaneously at the frequency of 2.45 GHz. This proposed antenna has the fundamental resonant frequency of 2.5 GHz with the minimum return loss of -39.9 dB. Furthermore, its impedance bandwidth is 460 MHz or 18.4% and 3-dB axial-ratio (AR) bandwidth is 360 MHz or 14.4% at 2.5 GHz.
A novel design of a microstrip-fed shorted square-ring slot antenna for circular polarization
(2007-07-01)
Chang, Kow-Ming
;
Lin, Ren-Jie
;
Deng, I-Chung
;
Ke, Qing-Xiang
;
電子工程學系及電子研究所
The design of a circularly polarized slot antenna fed by a single microstrip line is presented. The circularly polarized radiation is achieved by means of using a shorted square-ring slot. This proposed antenna has the fundamental resonant frequency of 2.4 GHz with the minimum return loss of -50.44 dB. The impedance bandwidth is 930 MHz or 38.7% referred to the resonant frequency, and it also has the 3-dB axial-ratio (AR) bandwidth of 310 MHz or 12.9% referred to the resonant frequency. In addition, this proposed antenna shows good performance of circular polarization (CP) radiation with the range of the lower 3-dB AR value covering elevation angles between -40 to 40 degrees. (C) 2007 Wiley Periodicals, Inc.