• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.3
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• pp.142-146
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• 2014

In this paper, an antenna which has quad band in GSM/DCS/PCS/Bluetooth is proposed. This structure is designed with miniaturization for wide band characteristic based on monopole antenna and log-periodic toothed trapezoid patch antenna which has slots. To achieve multi-bandwidth is used the microstrip line on the substrate. An antenna size is $35mm{\times}20mm$ on FR-4(${\varepsilon}r=4.4$) ground substrate of $35mm{\times}75mm{\times}1mm$ size. And proposed antenna is satisfied with impedance bandwidth(VSWR ${\leq}$ 3). The simulated maximum radiation gain is 1.92 dBi, 3.26 dBi, 3.97 dBi at the center frequency of 0.92 GHz, 1.97 GHz, 2.45 GHz, respectively.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.171-179
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• 2017

In this paper, microstrip antenna using multi-layer and folded structure for GPS application is presented for aircraft loading. Existing microstrip patch antenna used dielectric of high specific inductive capacity to miniaturize that cause smaller bandwidth and decline of efficiency due to dielectric loss. To compensate the existing flaws, Rogers TMM 10i(dielectric constant=9.8, loss tangent=0.002) is used for multi-layer dielectric miniaturization, and we construct folded radiating element on the surface of the dielectric applying perturbation effect. The antenna is designed in the bandwidth of GPS $L_1$ band, and the size of the antenna's radiating element is $20.3mm{\times}19.93mm$, and it gets 94.2% miniaturized characteristic of basic ${\lambda}/2$ microstrip patch antenna. Also the measured -10 dB bandwidth is 32.3 MHz(2.05%), 3 dB axial ratio bandwidth is 6.7 MHz(0.43%). Measured radiation patterns was maximum gain of 0.56 dBi at x axis polarization, 1.23 dBi at y axis polarization.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.3
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• pp.230-239
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• 2009

In this paper, we propose a novel on-glass antenna for FM radio reception in a recreation vehicle(RV). We use a multi-loop structure that takes advantage of a broad matching bandwidth and a high vertical radiation gain by efficiently utilizing a given space of a quarter glass in spite of the simple planar structure. Transparency of the antenna is also improved by adjusting the stripline widths based on the induced current distributions. The proposed antenna is printed on a quarter glass of a commercial vehicle and antenna performances such as the return loss and the gain are measured in a semi-anechoic chamber. The result shows the average gain of -9.67 dBi along the bore-sight direction($\theta=90^{\circ}$, $\phi=270^{\circ}$) in the FM radio band(80$\sim$l10 MHz), which is higher than a commercial monopole typed on-glass antenna($G_{ave}$=-12.49 dBi) and micro-antenna($G_{ave}$=-19.24 dBi) mounted on the roof of the RV.

• Journal of Korea Society of Digital Industry and Information Management
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• v.9 no.2
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• pp.11-15
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• 2013

We in order to use WLAN communication device planned wireless USB dongle internal antenna of 2.4 GHz/5.8 GHz band. So it uses square patch dual-wideband and quality is satisfactory and it designed print folded monopole antenna of the shape which is simple. The thickness of the antenna was fed by a $50{\Omega}$ coaxial cable feeding 1mm dielectric constant 4.4 FR4 substrate was used. The overall size of the antenna is $20mm{\times}50mm$. So the internal antenna is suitable. Measurement results of the fabricated antenna, the return loss of more than 10 dB in the two bands could be obtained. Radiation pattern has a maximum gain of 3.75 dBi value.

• Journal of information and communication convergence engineering
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• v.7 no.3
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• pp.263-267
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• 2009

Cylindrical monopole antenna is one of most promising candidates for multi-band applications such as PCS, WLAN, DMB, and UWB wireless services. In this research, we demonstrate that there exist two types of current distributions according to the exciting frequency in a double band cylindrical monopole antenna, in which double resonance is achieved by adjusting the coupling structure of the antenna base. The operating modes of current distributions are identified from CST software simulations, the standing wave mode in a lower band and the traveling wave mode in a higher band. Also it is noticed that the mode behavior is quite similar to a helical antenna, a standing-wave (resonance) mode and a traveling-wave (non-resonance) mode according to the electrical dimensions of antenna. The effective ranges for operating modes and design formulas of the double band antenna are derived from simulation and measured results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.314-317
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• 2004

On 9/5/2003, the planet probe “HAYABUSA” as MUSES-C project was launched by The Institute of Space and Astronautical Science. “HAYABUSA” has microwave discharge ion engines and these engines are characterized by their high efficiency and specific impulse in comparison with chemical engine. A large ion engine can be used as a planet explorer, while a small ion engine can be used as attitude control of small satellite. We have been developing a high thrust density microwave discharge ion engine using “Multi-Monopole Antenna”. The performance of this engine are: ion cost of 344W/A, propellant utilization efficiency of 52% and thrust density of 0.055mN/$\textrm{cm}^2$ for Kr gas flow rate of 2.5sccm, microwave(2.45㎓) power of 32W and acceleration voltage of l.4㎸.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.2
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• pp.370-375
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• 2011

In this paper, we propose an antenna module with high isolation between Tx and Rx in RFID reader module. The proposed module consists of a quadrafilar antenna and a directional coupler with a switchable dummy load to improve the directivity. The proposed module achieves the isolation higher than 20 dB between Tx and Rx. To show the validity of the proposed scheme, we have performed the measurement of tagging range and multi-tagging ability. The experiment results show that the detecting range and multi-tagging ability are enhanced by 81% and 200%, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.186-186
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• 2000

In the GPS/DR integrated system, the GPS position(or velocity) is used to compensate the DR output and to calibrate errors in the DR sensor. This synergistic relationship ensures that the calibrated DR accuracy can be maintained even when the GPS signal is blocked. Because of the observability problem, however, the DR sensors are not sufficiently calibrated when the vehicle speed is low. This problem can be solved if we use a multi-antenna GPS receiver for attitude determination instead of conventional one. This paper designs a two-antenna GPS receiver integrated with DR sensors. The proposed integration system has three remarkable features. First, the DR sensor can be calibrated regardless of the vehicle speed with the aid of two-antenna GPS receiver. Secondly, the search space of integer ambiguities in GPS carrier-phase measurements is reduced to a part of the surface of the sphere using DR heading. Thirdly, the detection resolution of cycle-slips in GPS carrier-phase measurements is improved with the aid of DR heading. From the experimental result, it is shown that the search grace is drastically reduced to about 3120 of the non-aided case and the cycle-slips of 1 or half cycle can be detected.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.485-488
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• 2005

The 2nd KOrea Multi-Purpose Satellite (KOMPSAT -2) has been developed by Korea Aerospace Research Institute (KARI) since 2000. Multi Spectral Camera (MSC) is the payload for KOMPSAT -2, which will provide the observation imagery around Korean peninsula with high resolution. KOMPSAT-2 has adopted X-band Tracking System (XTS) for transmitting earth observation data to ground station. For this, data which describes and controls the pre-defined motion of each on-board X-Band antenna in XTS, must be transmitted to the spacecraft as S-Band command and it is called as Tracking Parameter Files (TPF). In this paper, the result of the development of TPF Generation S/W for KOMPSAT-2 X-Band Antenna Motion Control.

• Journal of information and communication convergence engineering
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• v.9 no.2
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• pp.193-196
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• 2011

Transmit antenna selection techniques are prominent since they exploit the spatial selectivity at the transmitter side. In the literature, antenna selection techniques assume full knowledge of the channel state information (CSI). In this paper, we consider that the CSI is not perfectly known at the transmitter; however, a quantized version of the channel coefficients is fed back by the users. We employ the non-uniform Lloyd-Max quantization algorithm which takes into consideration the distribution of the channel coefficients. Simulation results show that the degradation in the BER of the system with imperfect CSI at the transmitter is tolerable, especially when the transmit diversity order is high.