• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.793-798
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• 2008

This paper presents a design of RFID(Radio Frequency Identification} tag antenna which has high sensitivity for car side mirror. A proposed tag antenna ($154\;mm{\times}66\;mm{\times}1;mm$) resonants at 900 MHz and has a wide bandwidth of 690 MHz($490\;MHz{\sim}1180\;MHz$). The measured gain and readable range of tag antenna are 5.8 dBd and 10 m, respectively. Radiation pattern and readable range of proposed tag antenna located on inside of a side mirror including a car body are measured at anechoic chamber. It has been confirmed that the readable range in the vicinity of $90^{\circ}$ has been expanded about 1.5 m by comparison with one of proposed tag antenna without of car body. Good performance of the proposed tag antenna was observed and proved by comparison of measured results of commercial tag antenna.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.623-627
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• 2014

In recent years, wireless communication technologies in human body have received an increasing attention and the research on an antenna that can be worn also has been actively conducted. In this paper, an wearable antenna that can receive GPS signal frequency is proposed. The antenna was manufactured by using a copper polyester fabric with thickness of 0.08mm as a radiator and a ground plate, and a goatskin with thickness of 0.7mm as dielectric substrate. Cutting edges placed in diagonal direction of square patch in order to obtain a circular polarization characteristic, and the conductive cloth and leather was laminated by using a conductive epoxy. First, goatskin dielectric constant was obtained through the simulation and measurement of resonance frequency of the three square patch antennas with different size. On the basis of the results, an antenna operating in the GPS band was designed and the performance of the antenna was validated by making the experiment. The change of the characteristic of the antenna that is located on the shoulder parts of the clothing and wearing person were measured. And it was confirmed that the reception sensitivity has a similar level as compared to the commercially produced ceramic GPS antenna.

• 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 the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4842-4848
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• 2015

This paper presents a comparison of communication performance between the reconfigurable beam-steering antenna and the omni-directional (loop) antenna during standstill and walking motion. Both omni-directional and reconfigurable antennas were manufactured on the same fabric (${\varepsilon}_r=1.35$, $tqn{\delta}=0.02$) substrate and operated around 5 GHz band. The reconfigurable antenna was designed to steer the beam directions. To implement the beam-steering capability, the antenna used two PIN diodes. The measured peak gains were 5.9-6.6 dBi and the overall half power beam width (HPBW) was $102^{\circ}$. In order to compare the communication efficiency, both the bit error rate (BER) and the signal-to-noise ratio (SNR) were measured using a GNU Radio Companion software tool and user software radio peripheral (USRP) devices. The measurement were performed when both antennas were standstill and walking motion in an antenna chamber as well as in a smart home environment. From these results, the performances of the reconfigurable beam steering antenna outperformed that of the loop antenna. In addition, in terms of communication efficiencies, in an antenna chamber was better than in a smart home environment. In terms of movement of antennas, standstill state has better results than walking motion state.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.102-106
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• 2014

In this paper, we investigate the realistic environment influence on the Hearing-Aid Compatibility(HAC) of the body-held device mock-up with a dual-band antenna. In detail, first, a dual-band internal antenna is designed considering the neighboring objects essential to a real attachable mobile device. This comes to reality by making its mock-up version. Second, the HAC of this device is simulated and measured for 'stand alone', and 'hand-held' cases. Particularly, the electromagnetic simulation of the designed antenna in the real device is verified by the standard measurement. Finally, the evaluated HAC is analyzed in terms of the relations with the bands, the mock-up environment and the hand effect.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.3
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• pp.301-307
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• 2002

A multilayer ceramic chip antenna with helical structure is analyzed to enhance the narrow bandwidth of conventional ceramic chip antennas. The simulations are performed by HFSS to verify the effects of structural parameters on impedance bandwidth. The multilayer ceramic chip antennas consist of a rectangular-parallelepiped ceramic body$({\varepsilon}_r=7.8,\; tan\; {\delta}=0.0043)$ and helical conductor patterns are embedded in the ceramic body using LTCC-MLC technology. 3D structure design of the multilayer ceramic chip antenna suitable for IMT-2000 (1,920~2,170 MHz) handset has been implemented, and experimental results are presented and discussed.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.331-337
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• 2015

A novel fully-printed microstrip antenna with negative first resonance and dual polarization is proposed. The radiator is printed on the 1-layer substrate instead of multilayers. The -1st resonance results from a composite right- and left-handed(CRLH) structure that has a circumferentially interlocked gap capacitively coupling a patch with a shorted-ring. This compact antenna is provided with a dual-polarization capability by creating two orthogonal linear polarizations in one body with coaxial feeds. The design is carried out by doing full-wave EM field simulation which is compared with the measurement of the fabricated antenna prototype. The measured results give the gain of 5 dBi and the efficiency of 78% at the -1st resonance mode as the center frequency of a downlink channel of the bandwidth over 20 MHz with 29 dB polarization isolation for mobile communication.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.342-342
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• 2010

This paper mainly focuses and describes four-armed dual-band rectangular type patch antenna using teflon of 0.54 mm thickness substrate for the application in personal wireless communications at about 2 GHz and 2.5 GHz frequency ranges. The dual-band patch antenna is obtained by embedding one centered and two pairs of rectangular patches on single body above the substrate. Details of the proposed antenna design are presented and discussed as a novel design with remarkable value of return loss (S11) of -28.68 dB and it is the most suitable for WiMAX applications as well.

• ETRI Journal
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• v.16 no.2
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• pp.27-41
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• 1994

A new mathematical model to predict the beam pointing instability of a nonconservative two-body satellite system in spinning injection mode has been developed by using Newton-Euler and projection methods. Since the on-axis and null axis of the omni antenna with toroidal pattern beam form a right angle, wobbling of the antenna on-axis is measured by determining the Euler angles which represent the orientation of the satellite's spin axis. Because of the complexity of the system which is a time varying, nonstationary, nonlinear dynamical system, a numerical method is used for the analysis. Computer simulation results present the effects of the mass distribution and internal mass motion on the antenna beam pointing.

• International Journal of Aeronautical and Space Sciences
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• v.17 no.3
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• pp.391-400
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• 2016

In satellite operations, stable maneuvering of a satellite's onboard antenna to prevent undesirable vibrations to the satellite body is required for high-quality high-resolution images. For this reason, the onboard antenna's angular rate is typically minimized while still satisfying the system requirement that limits the speed of the onboard antenna. In this study, a simple yet effective method, called the ground station searching method, is proposed to reduce the angular rate of a satellite's onboard antenna. The performance of the proposed method is tested using real flight data from the KOMPSAT-3 satellite. Approximately 83% of arbitrarily selected real flight scenarios from 66 test cases show reductions in the onboard antenna's azimuth angular rates. Additionally, reliable solutions were consistently obtained within a reasonably acceptable computation time while generating an onboard antenna tracking profile. The obtained results indicate that the proposed method can be used in real satellite operations and can reduce the operational loads on a ground operator. Although the current work only considers the KOMPSAT-3 satellite as a test case, the proposed method can be easily modified and applied to other satellites that have similar operational characteristics.