• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.805-810
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• 2014

In this paper, the characteristics of a series-fed dipole pair antenna with an end-aligned strip pair director are studied. In the proposed SDP antenna, two strip dipole antennas with different lengths and a ground reflector are connected trough a coplanar stripline. The strip pair director placed above the second dipole element are two rectangular-shaped strips and is aligned at the ends of the two arms of the second dipole. The variations on the antenna performance for different lengths and widths of the director are analyzed, and optimal design parameters for the enhancement of the bandwidth are obtained. The optimized SDP antenna is fabricated on an FR4 substrate, and the experimental results show that the antenna has a frequency band of 1.65-2.95 GHz for a VSWR < 2, which shows enhanced bandwidth compared to the conventional SDP antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.502-507
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• 2013

In this paper, a circular dual mode horn with modified aperture is proposed to improve a E/H-plane radiation pattern symmetry of a conventional oversized circular dual mode horn. The proposed antenna consists of a feeding section, a mode generation section and a phase matching section which has aperture shape transition from circle to ellipse or rectangle to improve a E/H-plane radiation pattern symmetry. To compare the performances between the proposed antenna and the convenional circular dual mode horn, the conventional circular dual mode horn and the proposed circular dual mode horn with rectangular aperture are fabricated and researched at 15 GHz. The measured results show that the conventional circular dual mode horn has 3.394 dB difference while the proposed antenna has only 0.539 dB difference between E and H-plane radiation patterns within the -11 dB beamwidth($53^{\circ}$) which is required beamwidth of the feed horn for the maximum aperture efficiency where f/d ratio of reflector antenna is 1.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.245-252
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• 2016

In this paper, the design of a double-dipole quasi-Yagi antenna (DDQYA) with a gain over 7 dBi at 1.70-2.70 GHz band is studied. The proposed DDQYA consists of two strip dipoles with different lengths and a ground reflector, which are connected trough a coplanar stripline. The length of the second dipole is adjusted to increase the gain in the low frequency band, whereas a rectangular patch director is appended to the DDQYA to enhance the gain in the middle and high frequency band. The effects of the length of the second dipole, and the length and width of the director on the antenna performance are analyzed, and final design parameters to obtain a gain over 7 dBi are obtained. A prototype of the proposed DDQYA is fabricated on an FR4 substrate, and the experimental results show that the antenna has a frequency band of 1.60-2.86 GHz for a VSWR < 2, and measured gain ranges 7.2-7.6 dBi at 1.70-2.70 GHz band.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.70-73
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• 2012

In this paper, we introduce a design method for a quasi-Yagi antenna (QYA) with broadband characteristics of an impedance bandwidth ratio of > 2 : 1 and a gain of > 4 dBi. The QYA is fed by a microstrip line fabricated on a coplanar strip line and it consists of 3 elements; a planar dipole, a nearby director close to the dipole, and a ground plane reflector. By placing a rectangular patch-type director with large width near to the dipole driver, broadband characteristics are achieved. An optimized 3-element QYA for operation over 1.6-3.5 GHz (bandwidth ratio 2.2 : 1) is fabricated on an FR4 substrate with a size of $90mm{\times}90mm$ and tested experimentally. The results show an impedance bandwidth of 1.56-3.74 GHz (bandwidth ratio 2.4 : 1) for VSWR < 2, a peak gain of 4.41-6.53 dBi, and a front-to-back ratio (FBR) > 13.6 dB within the bandwidth.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.760-765
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• 2012

In this paper, we studied a design method for a quasi-Yagi antenna (QYA) with broadband characteristics of an impedance bandwidth ratio greater than 2 : 1 and a gain > 4 dBi. The QYA is fed by a microstrip line fabricated on a coplanar strip line and it consists of 3 elements; a planar dipole, a nearby director close to the dipole, and a ground plane reflector. By placing a wide rectangular patch-type director near to the dipole driver, broadband characteristics are achieved. An optimized 3-element QYA for operation over 1.6-3.5 GHz (bandwidth ratio 2.2 : 1) is fabricated on an FR4 substrate with a size of 90 mm by 90 mm and tested experimentally. The results show an impedance bandwidth of 1.56-3.74 GHz (bandwidth ratio 2.4 : 1) for VSWR < 2, a peak gain of 4.2-6.3 dBi, and a front-to-back ratio (FBR) > 13.6 dB within the bandwidth.