• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.785-790
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• 2008

In this paper, a new balun is proposed. This proposed balun has a DGS(Defected Ground Structure) pattern on the ground plane. The transmission-line is transformed by microstrip-to-slotline transition. DGS pattern on the ground plane and transition of the lines can be easily made a property of the balun. Resonance frequency of the DGS leads to operating frequency of the balun. Also the transition produces $180^{\circ}$ out-of-phase between two output ports without additional transmission line. In this paper, a new balun with VPDGS(Vertically Periodic Defected Ground Structure) effectively lower the operating frequency. To validate the proposed design method, the new balun is designed, fabricated and measured at 2 GHz.

• Journal of electromagnetic engineering and science
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• v.13 no.3
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• pp.178-185
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• 2013

This paper introduces a high-efficiency, high-gain, broadband quasi-Yagi antenna, and its four-element array for use in 60-GHz wireless communications. The antenna was fed by a microstrip-to-slotline transition consisting of a curved microstripline and a circular slot to allow broadband characteristics. A corrugated ground plane was employed as a reflector to improve the gains in the low-frequency region of the operation bandwidth, and consequently, to reduce variation. The single antenna yielded an impedance bandwidth of 49 to 69 GHz for $|S_{11}|$ <-10dB and a gain of >12.0 dBi while the array exhibited a bandwidth of 52 to 68 GHz and a gain greater than 15.0 dBi. Both proposed designs had small gain variations (${\pm}0.5$ dBi) and high radiation efficiency (>95%) in the 60-GHz bands. The features of the proposed antenna were validated by designing, fabricating, and testing a scaled-up configuration of the single antenna at the 15-GHz band. The measurements resulted in an impedance bandwidth of 13.0 to 17.5 GHz for $|S_{11}|$ <-10dB, a gain of 10.1 to 13.2 dBi, and radiation efficiency in excess of 88% within this bandwidth. Additionally, the 15-GHz antenna yielded quite symmetric radiation profiles in both E- and H-planes, with a high front-to-back ratio.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.610-618
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• 2000

A T-shaped microstripline -fed printed slot antenna is anlayzed by using the transmission line model(TLM) in this paper. Microstrip-slotline junction is modeled by employing a transformer and the transformer turn ratio is derived empirically. The method is extended to the case of $1\times2,l\times4$array antennas. Return loss results obtained by using the transmission line model. The maximum measured results and demonstrated the usefulness of the transmission line model. The maximum bandwidths of a single antenna, $1\times2,l\times4$ array antennas are 28.5%, 47.8%, and 50.9%, respectively, for the VSWR$\leq2$. The gain of $1\times4$ array antenna is 7.97dBi and the beamwidth is about $27^{\circ}$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.5
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• pp.103-115
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• 2012

In this paper, design and performance evaluation of Tapered Slot Antenna for IR-UWB which propagates impulse radio is performed. TSA which has directional characteristic in UWB band should have low radiation loss and minimized impulse radiation distortion. In order to achieve these objectives, the paper designed wide band Impedance transformer and microstrip-slotline transit region structured TSA feeder line. By using the fabricated TSA, the radiation pattern was measured in the radio anechoic chamber. Pulse fidelity and distortion equation was induced to evaluate time domain characteristics according to the impulse radiation. Pulse fidelity of Impulse radiation show favorable results more than 93% within ${\pm}30^{\circ}$ beam width.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.299-307
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• 2013

In this paper, design of UWB Antenna which propagate impulse by pulse fidelity and distortion equation was induced and applied. UWB Antenna which has directional characteristic in UWB band should have low radiation loss and impulse radiation distortion. As a result, the paper designed wide band impedance transformer and microstrip slotline transit region structured antenna feeder line. By using the fabricated UWB antenna, the radiation pattern was measured in the radio anechoic chamber. Pulse fidelity of impulse radiation show good results more than 93% within ${\pm}30^{\circ}$ beam width.