• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.21-30
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• 2004

This paper describes the design of RF link between RSE and OBU of ETCS and the analysis of the antenna beam pattern to get a proper communication area in the cross direction and traveling direction of lanes. This stage should be performed prior to determination of system requirements of ITS service based on active DSRC. This study is important and fundamental technical analysis to design and implement base station of ETCS.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.5
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• pp.388-396
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• 2019

This paper describes the RF(Radio Frequency) interference on the GNSS receiver due to the S-band signals transmitted from the transmitters in the Test Launch Vehicle, and analyzes the cause of the RF interference. Due to the S-band signals that have relatively high power levels compared with GNSS signals, an LNA(Low Noise Amplifier) in the active GNSS antenna was saturated, and the intermodulation signal within GNSS in-bands was produced in the LNA whenever two S-band signals were received from the GNSS antenna. For these reasons, the C/N0 of the satellite signals in the GNSS receiver was attenuated severely. The design of the LNA was changed in order to protect the RF interference due to the S-band signals and the suppression capability of the RF interference was confirmed in the new LNA through the comparison of the old LNA.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.78-79
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• 2009

본 연구에서는 ZnO계 투명전극 소재를 이용하여 RFID 태그 안테나에 적용 가능성 여부를 확인하였다. Si 기판위에 RF 스퍼터링 공정에 의해 Ga-doped ZnO 투명 마이크로스트립 스파이혈 안테나를 $2{\mu}m$를 증착하여 구현하고 그 전기적 특성을 측정하였다. HFSS 전자계 시뮬레이터를 사용하여 13.56MHz HF 주파수 대역에서 태그 안테나로서의 가능성을 검증한 후 Ga-doped ZnO 타겟을 사용한 RF 스퍼터링 공정에 의하여 스파이럴 안테나 패턴을 구현하였다. 마이크로스트립 선폭 및 선 간격을 $50\sim200{\mu}m$때 영역에서 조절하면서 안테나 패턴을 설계하였다. S 파라메터, 자기공진주파수 및 Q값을 시뮬레이션으로부터 도출하였다. Al $2{\mu}m$ 증착한 시편에 비하여 약 -10dB 정도의 이득저하가 발생하였으나 리더-태그를 밀착시킨 조건에서 1.7V (13.56MHz) 전압검출이 가능하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.65-67
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• 2015

In this paper, small WLAN antenna was designed and investigated. Proposed antenna was configured for microstrip patch antenna ($29mm{\times}29mm$) that was mounted on RF4 dielectric substrate (relative permittivity 4.4, thick 1.6mm, tangent loss 0.025) with $45mm{\times}45mm$. In order to obtain a wide band characteristic, the cutting process was 3.2mm diagonal corners of the patch antenna located on the top of the substrate. Antenna feeding position for 50 ohm impedance matching was decided to be 5.1mm at the central axis in the horizontal direction. As a result, frequency bandwidth satisfying the condition of VSWR<2dB was 2.365-2.45GHz (85MHz, 3.53%) for considering WLAN.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.766-772
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• 2012

In the present study, wideband microstrip monopole slot antennas which can be applied to the RF4CE Zigbee remote controller are designed. First I-shaped monopole slot antenna which has ${\lambda}g/4$ length at 2.45GHz is designed. In particular, a conducting via is used to connect the microstrip feed line and the ground plane surrounded with the etched slot for the bandwidth improvement. In order to reduce the antenna size, it is changed into L-shaped and T-shaped monopole slot antennas for which improve results of antenna performance are observed. In case of T-shaped monopole slot antenna, impedance bandwidth(VSWR<2) is about 3.32GHz, and also its radiation efficiency and gain is more than 90% and 2.1dBi respectively at whole operating frequency range. In particular, all of proposed monopole slot antennas have the end-fire radiations which has a maximum radiation power toward direction of open ends of monopole slots.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.143-150
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• 2007

A meander slot antenna with open-end fed by a microstrip line which can be used at 400 MHz ISM band is newly proposed. The main difference between the proposed slot antenna and the previous slot antenna is the introduction of the open-end to miniaturize the previous meander slot antenna in the space restricted within narrow limit. In order to check the validity of the proposed antenna, the resonant frequency and radiation pattern of the proposed antenna have been simulated and examined. Good agreements between simulated results and measured results have been observed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.8
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• pp.632-639
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• 2018

This paper presents a single antenna radar sensor with a Ku-band radar transceiver IC realized by 130 nm CMOS processes. In this radar receiver, sensitivity time control using a DC offset cancellation feedback loop is employed to achieve a constant SNR, irrespective of distance. In addition, the receiver RF block has gain control to adjust high dynamic range. The RF output power is 9 dBm and the full chain gain of the Rx is 82 dB. To reduce the direct-coupled Tx signal to the Rx in a single antenna radar, a stub-tuned hybrid coupler is adopted instead of a bulky circulator. The maximum measured distance between the horn antenna and a metal plate target is 6 m.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.3
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• pp.425-431
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• 2015

Beamspace Multiple-Input Multiple Output(MIMO) system can transmit multiple data by using Electronically Steerable Parasitic Array Radiator(ESPAR) antenna which has single Radio Frequency(RF)-chain. Beamspace MIMO system can reduce complexity of the system and size of antenna in comparison with the conventional MIMO system because of characteristic of ESPAR antenna using the single antenna and the RF-chain. Heretofore, only the research of transmitting single-carrier has been conducted by the use of beamspace MIMO system. Therefore, in this paper, we propose beamspace MIMO system based on Orthogonal Frequency Division Multiplexing(OFDM) for transmitting the multi-carrier and analysis the performance of this system. We find a proper reactance value which has good performance because proposed system changes the performance by the reactance values of parasitic elements. and we confirm that performance of the proposed system is similar to conventional MIMO system based on OFDM.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.1
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• pp.45-52
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• 2009

In this paper, a new rectenna is presented for the wireless transmission of microwave power using dipole antenna (Quasi Yagi effect) and rectifier of CPS resonator structure. The dipole antenna with CPW feedline has high peak gain than a general dipole antenna. A ground plane of CPW is used to reflect a dipole as a Yagi antenna. Therefore, the new rectenna receives the RF power better than the one using general dipole. A RF-to-DC conversion efficiency of 61 % using a 1.4 $k{\Omega}$ load resistor is obtained at 5.8 GHz.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.108-113
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• 2006

This paper includes the test results of KOMPSAT-2 payload downlink system which were measured for the purpose of performance verification. The antenna beam patterns which indicates the status of the interface & antenna itself, were measured as well as the antenna VSWR. The checkout of the transponder & its spectrum was followed and this made sure that there was no spurious output distinguished. Finally a test for BER verification was conducted between satellite and receiving system for their compatibility through the antenna-to-antenna connection using an antenna hat. Verification tests for an RF system should be performed after relocation, integration and test for environments in order to make sure that no degradation happens.