• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.6
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• pp.605-612
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• 2011

In this paper, we designed detachable T-DMB receiver antenna on the windshield of the car. Designed antenna is composed of only copper and feeders. To escape completely from driver's sight, it exists edging of windshield. Proposed antenna by considering body of properties and characteristics of the antenna input impedance have T-DMB frequency band(174~216 MHz). Proposed flexible antenna with Common Mode Stub is satisfied characteristics less than -5 dB antenna input return loss regardless of installation position on windshield.

• Journal of Electrical Engineering and Technology
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• v.10 no.2
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• pp.634-640
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• 2015

This paper deals with the design of a microstrip line feed toppled T shaped microstrip patch antenna that gives dualband characteristics at 4 GHz and 6.73 GHz respectively. The simulation of proposed antenna geometry has been performed using method of moment based IE3D simulation software. A radial basis function neural network (RBFNN) is used for the estimation of bandwidth for dualband at 4 GHz and 6.73 GHz respectively. In RBFNN model, antenna parameters such as dielectric constant, height of substrate, and width are used as input and bandwidth of first and second band is considered as output of the network. To validate the RBFNN output, an antenna has been physically fabricated on glass epoxy substrate. The fabricated antenna can be utilized in S and C bands applications. RBFNN results are found in close agreement with simulated and experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.131-139
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• 2011

In this paper, we propose a double-faced window printed antenna for aircraft applications. The proposed antenna structure consists of a feeding line and a multi-loop radiator located on different sides of the window to use the limited given-area effectively. The proposed antenna is optimized by the genetic algorithm in conjunction with the FEKO EM simulator. The optimized antenna is built and installed on a 1/10 sized KUH-Surion mock-up and antenna performances such as the reflection coefficient and the radiation patterns are measured. The optimized antenna shows a half power matching bandwidth of about 33 % at 60 MHz and an average bore-sight gain of about -3.49 dBi. To verify the reception capability of the optimized antenna, we simulated the received power according to a flight scenario. The result confirms that the optimized antenna shows a minimum received power level above -60 dBm at a range of 200 km, which is similar to the pole antenna that is currently used as a FM voice antenna for KUH-Surion.

• Journal of electromagnetic engineering and science
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• v.11 no.1
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• pp.1-4
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• 2011

In this letter, we propose a novel tag antenna that has low performance degradation with nearby dielectric material. We obtained a stable reading performance and a broad matching bandwidth on nearby dielectric materials by employing a T-matching network with thick line width and capacitively slot-loaded arms. We then built the proposed antenna and measured the tag sensitivity to examine the reading characteristics with nearby dielectric materials. The measured results clearly demonstrate stable tag sensitivity with various nearby dielectric materials, such as foam, acrylic-plastic, glass, and ceramic plates. To more closely observe the antenna characteristics with nearby dielectric materials, we also examined the impedance variation and surface current distribution with respect to the dielectric constant of nearby target objects, which ranged from $1{\times}{\varepsilon}_0$ to $16{\times}{\varepsilon}_0$.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.152-156
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• 1989

Parameters of a microstrip patch antenna such as the resonant frequency, radiation conductance, and the bandwidth are calculated. The rectangular microstrip patch antenna fed by a microstrip transmission line is fabricated and its resonant frequency, radiation pattern, and input voltage standing wave ratio are measured. The measured resonant frequency for 13.0mm$\times$9.7mm copper clad woven PTFE/glass laminate plate is 9.06Ghz, where the calculative is 9.00Ghz. And the measured vswr shows that the bandwidth of the antenna is 225MHz for vswr less then 2.0 which the calculated quality factor of the patch gives the bandwidth OF 280ghZ. The measured radiation pattern for 5 element as well as 4 element patch array shows less then 4dB deviation in the first side lobes from the designed values for both E and H plane pattern. This diviation is believed to be the power division errors of the power divider.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.140-147
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• 2011

In this paper, we propose a novel feeding method that uses a windshield ground in a vehicle. The feeding method enables for various antennas to integrate easily in a vehicle windshield. To connect a coaxial feeding cable directly to the windshield ground, we inserted a coaxial-to-ground adapter between the cable and the ground, and reflection coefficients using the proposed feeding method were compared to that using a conventional feeding method. The size and position of the windshield ground were optimized in order to achieve a high radiation gain in the azimuth direction. Then the triangular WiBro patch antenna, incorporating the proposed feeding method, was designed and installed on a rear windshield of a commercial sedan. The antenna using the proposed feeding method shows a similar reflection coefficient, and it shows 2 dB increased average azimuth radiation gain compared to that using a conventional sash ground method. These results demonstrate that the proposed feeding method can be applicable for integrating multiple antennas in a rear windshield.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.154-160
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• 2009

This paper describes a wide bandwidth RFID tag antenna design for protection of connection part between chip and antenna. A proposed tag antenna size, a resonant frequency and bandwidth are $53{\times}10{\times}1\;mm$, 900 MHz and 800 MHz($500{\sim}1,300\;MHz$) at -10 dB below, respectively. The dielectric materials with different relative permittivity such as polyethylene, glass and silicon were applied for protection of connection part between the proposed antenna and chip on the way of whole and partial housing. The measured return loss and radiation pattern agreed well with the calculation results. The read range of the proposed tag antenna without any housing and of tag antenna with housing covered over all by silicon with 3 mm thickness were observed about 5 m and 4 m, respectively.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1511_1512
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• 2009

This paper presents a polarization switching antenna integrated with silicon RF MEMS SPDT switches in the form of a package. A low-loss quartz substrate made of SoQ (silicon-on-quartz) bonding is used as a dielectric material of the patch antenna, as well as a packaging lid substrate of RF MEMS switches. The packaging/antenna substrate is bonded with the bottom substrate including feeding lines and RF MEMS switches by BCB adhesive bonding, and RF energy is transmitted from signal lines to antenna by slot coupling. Through this approach, fabrication complexity and degradation of RF performances of the antenna due to the parasitic effects, which are all caused from the packaging methods, can be reduced. This structure is expected to be used as a platform for reconfigurable antennas with RF MEMS tunable components. A linear polarization switching antenna operating at 19 GHz is manufactured based on the proposed method, and the fabrication process is carefully described. The s-parameters of the fabricated antenna at each state are measured to evaluate the antenna performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.12
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• pp.1007-1012
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• 2017

In this study, we performed the deployment test of shape memory polymer specimens for space antenna design. Poly(cyclootene) was cross-linked by dicumyl peroxide to make a PCO shape memory polymer. A miniature specimen with 120 mm diameter for a deployable antenna was fabricated with the PCO shape memory polymer. To investigate the deployment performance, the folded specimen as a temporary shape was heated by two heaters to the $15^{\circ}C$ higher temperature than the glass transition temperature of shape memory polymer. Firstly, the specimen was installed horizontally and tested. The deploying motion was captured by a digital camera and analyzed by a Tracker program. To reduce the effects of gravity, the specimen was installed vertically and tested again. The deployment performance of a shape memory polymer was investigated by comparing the results of horizontal and vertical installation tests.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.41-48
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• 2022

This study is a study that designed in-building antennas with improved orientation to improve 5G quality in buildings as 5G is stabilized and more and more traffic is expected to occur in buildings. Instead of applying the forward arrangement of antenna elements, which is the Yagi antenna propagation orientation principle, the antenna design method of vertical arrangement applied to the base station antenna was proposed, and it was confirmed through experiments that antenna orientation increased. According to the experimental results, the directivity did not increase significantly within 10m of the separation distance from the antenna, but the directivity increased by about 3dB at the distance separated by more than 10m. Considering that the wireless environment in the building has various variables such as structure of internal structure, materials such as concrete and glass, closed space, and walls, it is expected that antenna with improved orientation can expand the scope of 5G quality improvement and maintain stable communication service in the building.