• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.549-555
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• 2011

In this paper, inverted triangle structural planar monopole antenna with Edge for UWB Communication (3.1 ~ 10.6 GHz) is presented. The antenna have broadband property structurally through inverted triangle structural planar monopole which have edge. Monopole and ground of proposed antenna exist on coplanar plane, and excite as CPW. It used FR4 dielectric substrate of ${\epsilon}_r=4.4$, and the size is $20{\times}20{\times}1.6mm$. Return loss is more than - 10dB in 3.1 ~ 10.1 GHz (7.0 GHz). Radiation pattern is about the same that of dipole antenna at all frequency. At measured result, max gain is 8.44 dBi at E - plane.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.6
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• pp.1083-1090
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• 2009

In 18GHz using unified data transmission in a subway and railway, Influence of the multipath fading is big and an arrival range of the micro wave takes the influence greatly according to the transmit angle and receive angle because it not diffracted. This thesis analyzed microwave property underground tunnel and ground railway at unified data transmission in subway and railway. Antenna gain of directional antenna many used unified transmission in an subway and railway, is used 15dBi and 10dBi in simulation. Transmitter's property is compared underground tunnel to ground railway about curved railway of R=100, R=200, R=400. Specification of transmitter is used sample unified transmission system in subway and railway of KRRI(korea railroad research Institute). Transmitter's power is 20dBm and Reciever's sensitivity is -90dBm. According to result of simulation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2325-2331
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• 2012

Planar square-spiral antenna using a strip conductor is proposed and analyzed for RFID system in UHF band operating from 860MHz to 960MHz. By varying the length of common line, detached distance, strip line-space, strip line-width and the number of spiral turn, the optimized antenna are designed and fabricated in compact size without a matching-stub between the input port of the proposed antenna and RFID tag chip. From the optimized results, the frequency bandwidth in VSWR<2 has covered 100MHz in the RFID UHF band. The antenna gain has obtained 3.5dBi at the center frequency of 910MHz and the desired beam pattern has shown directional pattern on elevation and azimuth angle. Therefore, the proposed antenna is suitable for practical RFID applications requiring various tag chips with the specific input impedance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.233-240
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• 2007

In this paper, the broadband cross monopole antenna is presented and the radiation characteristics are investigated. The presented broadband cross monopole antenna is composed of the cross monopole element and the folded short stub, which has a excellent band characteristics more than the existing cross monopole antenna. To conform the broadband characteristics of the presented antenna, the experimental antenna is designed, fabricated, and its radiation characteristics are measured in $1.75\sim2.655\;GHz$. It is shown that the designed antenna has the nondirectional pattern in the horizontal plane, the directional pattern in the vertical plane, VSWR less than 1.5, and gain in $2.17\sim4.87\;dBi$. From these results, the presented antenna is conformed as a broadband indoor antenna which can be used for PCS, WCDMA, Wibro, and satellite DMB band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.12
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• pp.1327-1336
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• 2007

In this paper, we propose a reconfigurable antenna which operates as a disk-loaded dipole antenna and a folded dipole antenna alternatively using RF on/off switches. The antenna can change its effective length to achieve dual-band operation; operates as the folded dipole antenna for stepping up the radiation resistance in low frequency band of $20{\sim}300$ MHz, and as the disk-loaded dipole antenna for an omni-directional radiation pattern (horizontal plane) and a donut-shaped radiation pattern (vertical plane) in high frequency band of $300{\sim}1.3$ GHz. In the low band, the proposed antenna shows higher gain than a conventional dipole antenna with a reduced antenna size. In the high band, the antenna maintains a broad beamwidth of about $80^{\circ}$, thus the antenna can be applicable to antennas for direction finding applications.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.1
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• pp.286-290
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• 2017

In this paper, we have proposed a hexagonal patch UWB antenna with a band notch characteristic where the notch band of 5.15 ~ 5.85 GHz band of WLAN was induced by inserting a circular slit in the patch. The impedance bandwidth of the proposed antenna meet the band width criteria of UWB communication system where is mentioned as frequencies range form 3.1 ~ 11.8 GHz. The characteristic band at 5.2 ~ 5.8 GHz notch band was observed. The radiation pattern of the antenna shows a directinal radiation pattern at $0^{\circ}$ and $180^{\circ}$ in XZ-plane and YZ-plane is an omni-directional pattern, respectively. In addition, it is observed that increase in frequency results in increases of the antenna gain whereas the notch band section is decreased. The proposed antenna was designed TRF-45 substrate with thickness of 1.62 mm, a loss tangent of 0.0035, a relative permittivity of 4.5 and designed were used Ansys Inc. HFSS.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.39-46
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• 2014

In this paper, to operate 2.4 GHz Inverted-L antenna with On-Board Broadband characteristics is proposed. The antenna was designed on the system board, the bandwidth by adjusting the reactance of the antenna that was formed common-mode and differential-mode on the antenna stubs has been improved. The system size is $80mm{\times}60mm$, the size of the antenna was limited to $30mm{\times}60mm$, the thickness of FR4 dielectric substrate is 0.8 mm, FR4 dielectric constant 4.4 is used. The experimental results, the bandwidth from 17.2 to 24.1 %, the gain is 3.01~4.71 dB, omni-directional radiation pattern characteristics were obtained. By a mobile terminal design applying the results of the paper, the handset's price competitiveness and production efficiency can be improved.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.6
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• pp.989-996
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• 2017

The proposed directional pencil beam antenna consists of a waveguide feeder with bended elliptical conductor plate feed and a parabolic curved reflector. Two rectangular apertures located at the broad wall near the end of the feed waveguide inserted from behind the reflector are located at the focus of the reflector and emit electromagnetic energy with bended elliptical conductor plate. This plate is designed to reflect electromagnetic energy primarily and to face the main reflector. The two rectangular apertures located at the waveguide end have inwardly protruding tabs for impedance matching of the antenna system, the shape of the tabs is a truncated oval. The proposed parabolic reflector antenna has a diameter of 400 mm and a focal length of 134.23 mm. The antenna gain is 33.68 dBi at the center frequency of 16.5 GHz, the beam width is $3.3^{\circ}$ and the reflection loss is -15 dB. Using the HFSS-IE, simulation results are performed to validate the proposed antennas.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.247-255
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• 2011

The optical performance of LLF(Lenticular Lens Film)-based backlight was studied by using optical simulation as functions of the aspect ratio and the refractive index of lenticular lenses. In order to perform reliable simulation, the BSDF(bi-directional scattering distribution function) of the scattering dots on the bottom surface of the light guide plate was obtained as a superposition of the Lambertian and the elliptic Gaussian distribution components by comparing the experimental results and the simulation for the luminance distribution on the light guide. Based on this approach, an appropriate BSDF of the scattering dots of the light guide was constructed. The resultant values of the optimized aspect ratio and the refractive were found to be 1.25 and 1.65, respectively. In spite of the hybrid aspects of LLF incorporating both diffusing and collimating functions, the optical performance, in particular the on-axis luminance of LLF-based backlight was inferior by about 20% compared to that of conventional backlights adopting one prism film. However, the combination of two lenticular lens films resulted in comparable luminance gain as well as smooth decrease in the luminance with the viewing angle without exhibiting any side lobes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.1 s.116
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• pp.24-30
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• 2007

A windmill-shaped loop antenna is designed for polarization diversity. Its circumference is almost 10 times that of a conventional small loop antenna whose circumference is less than ${\lambda}/10$ but its the radiation pattern is omni-directional. An identical parasitic element is placed over the radiator to match the antenna input impedance. An equivalent transmission line and RLC circuit models are shown to fully describe for the windmill-shaped loop antenna. The proposed antenna has a bandwidth of 6 % with input VSWR less than 2:1 and a polarization purity of 15 dB at 2.6 GHz, and the gain of 1.5 dBi. The simulated and measured results show fairly good agreement.