• Proceedings of the IEEK Conference
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.105-106
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• 2007

A slot antenna with bazooka balun is designed and implemented for PCS repeater. The proposed antenna improved the return loss and radiation pattern of the slot antenna as combining with the bazooka balun. The antenna was designed by using 3D simulations program, MWS (Microwave Studio). The test result of the slot antenna shows that the return loss is under -10 [dB] for all frequency bands of interests in PCS and maximum gain is about 5.59 [dBi]. And the antenna also shows omni-directional radiation pattern.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제25권4호
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• pp.381-386
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• 2014

In this paper, the effect of slot antenna's location in the radiation performance and impedance bandwidth was analyzed. The proposed antenna was designed to operate at Wi-Fi band(2.4~2.5 GHz) when the slot antenna is located at the center of the ground plane, the proposed antenna has a bandwidth of 340 MHz(2.24~2.58 GHz) under voltage standing wave ratio of = 2 and achieves average realized efficiency of 69 % over Wi-Fi bands.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제19권5호
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• pp.515-522
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• 2008

In this paper, a slot antenna with built-in Bazooka balun aimed for a WiBro repeater was designed and fabricated. The return loss and radiation pattern of the slot antenna were improved due to the introduced Bazooka balun. This balun brings about even radiation pattern and keeps the stabilized coverage of repeater And it is easy to unite this balun with the antenna body by providing the terminal of Bazooka balun with screw shape. H-type slot was used to reduce the size of the antenna, and the slot antenna was fabricated in the structural symmetry with respect to a feeding point to afford the omni-directional radiation pattern. The simulated results were obtained by MWS(Microwave Studio Simulator) of CST company, and the measurement on the proposed antenna was conducted in an anechoic chamber equipped with a network analyzer and a far field measurement system. The measured peak gain shows 5.75 dBi and the average gain is above -0.8 dBi. The return loss remains below -12.35 dB for all frequency bands in WiBro regarded as a good performance.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 한국전자파학회 2000년도 종합학술발표회 논문집 Vol.10 No.1
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• pp.399-403
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• 2000

A new type of collinear antenna called short-ended coaxial slot-coupled strip array antenna is investigated theoretically. The antenna has an advantage of structural simplicity. The integral equations are derived for the proposed structure by use of the Fourier transform and mode expansion, and the simultaneous linear equations are obtained. The slot electric field and strip current are then obtained by solving the simultaneous linear equation. The effects of slot and strip number on the radiation efficienty, beamwidth and directivity gain are also presented.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제20권3호
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• pp.273-279
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• 2009

In this paper, an antenna which has dipole-like radiation pattern and low profile is proposed. The antenna is composed of four elements slot array based on L-shaped 0.43 $\lambda_g$ slot element. It presents a omni-directional radiation patter in the azimuth plane and has a null toward broad-side direction. In the design, a small mono-pole antenna which acts as a large capacitance element, combined with the partially removed ground plane by four L-shaped slots. As a result, these structure act as a LC resonator for radiation. The measured result shows, the impedance bandwidth(VSWR$\leq$2) of the proposed antenna is 60 MHz(2.35$\sim$2.41 GHz). The measured maximum radiation gain and efficiency of proposed antenna is 0.02 dBi, 56.7 % at center frequency 2.38 GHz, respectively. The proposed antenna can be applied to wireless tan access point system.

• Journal of the Korean Institute of Telematics and Electronics A
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• 제32A권7호
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• pp.23-29
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• 1995

A characteristic mode theory for longitudinal slot of arbitrary width in the outer conductor of coaxial waveguide is applied for calculating the characteristic magnetic currents, the characteristic fields, radiation patterns, and the fields evershere(inside and outside the guide, and in the aperture region). Numerical results of the equivalent magnetic currents and the radiation patterns are compared with those obtained by use of the method of moments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• 제9권5호
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• pp.630-639
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• 1998

In this paper, a T-shaped microstrip feed line is proposed for a better impedance matching to the microstrip slot antenna in a various range of slot widths. It was found that the bandwidth of this antenna is proportional to the slot width. It was also found that the radiation resistance of this feed line structure is quite constant and low regardless to the slot width. A slot antenna with T-shaped microstrip feed line is analyzed by using the FDTD method. At first, the propagation process of the reflected wave and the electric field distribution in the time domain is calculated respectively. The antenna parameters also are optimized to get maximum band width, return loss, input impedance, and radiation pattern in the frquency domain by Fourier transforming the time domain results. From the computed results, the optimum slot antenna is designed and fabricated. When the slot width is 16 mm, approximately 35% of bandwidths are obtained without a matching circuit. These computed results using FDTD method were in relatively good accordance with the measured values.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제22권2호
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• pp.298-305
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• 1997

In this paper, the radiation characteristics of a slot annenna in conduction cylinder covered with a moving isotropic plasma layer are analyzed. Integral representations of the eletromagnetic fields in the spectral domain radiated through the plasma layer are derived and converted into the fields in the spacial domain by saddle-point ingegration. Radiation null which brings about distorion in the radiation parrern is explained by the zero of integrand in an asymptotic integral as a function of plasma and velocity parameters. Numerical results for a radiation null calculated from various plasma and velocity parameters correspond to the results of planner structure.

• Journal of electromagnetic engineering and science
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• 제17권2호
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• pp.71-75
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• 2017

A dual-band tunable-slot-type ground radiation antenna is proposed. The feeding structure consists of a coplanar waveguide and a lumped capacitor to excite currents for first- and second-order resonant modes of the ground. The resonant frequencies of both bands are controlled using a series combination of a capacitor and an inductor. The proposed design may be an attractive choice for mobile devices owing to its compact geometry and tunable operating frequencies. The measurement and simulation results of the proposed antenna show good agreement, indicating good impedance matching and radiation performance.

• Journal of Advanced Navigation Technology
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• 제21권4호
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• pp.353-358
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• 2017

In order to reduce the size of the previous stepped slot antenna for UWB applications(3.1 ~ 10.6 GHz) to half, an open ended stepped slot antenna is proposed. The proposed antenna consists of a stepped slot etched on the ground plane as radiation part and a microstrip feed-line with rectangular patch on the top plane for wideband impedance matching. The proposed antenna is designed and fabricated on the FR4 substrate with dielectric constant of 4.3, thickness of 1.6 mm and size of $28.5{\times}32mm^2$. The measured impedance bandwidth (${\mid}S_{11}{\mid}{\leq}-10dB$) of the fabricated antenna is 7.99 GHz(3.01~11 GHz) which is sufficient to cover UWB band (3.1 ~ 10.6 GHz). In particular, it has been observed that antenna has a good omnidirectional radiation patterns and high gain over the entire frequency band of interest even though the size of the proposed antenna is reduced to half when compared with the previous antenna.