• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.8
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• pp.687-693
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• 2018

In this paper, we studied on the thermal design of the active antenna system for stable performance considering thermal reliability. The active antenna has high performance and heat flux elements in T/R modules. Thermal heating of elements in T/R modules has to be dissipated effectively and the antenna has to be operated over the range of suggested temperature by the thermal design. T/R modules of high heat flux in the active antenna can be dissipated effectively by liquid cooling. In this study, we studied on the thermal design including the liquid cooling system to optimize the thermal performance of the active antenna. And the thermal design was verified by numerical analysis.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.55-67
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• 2003

본 고에서는 차세대 무선통신용 초소형 단말기 구현에서 RF 시스템의 성능 개선에 크게 기여하게 될 RF 집적형 안테나 기술 현황과 향후 발전 방향이 제시된다. 고성능을 유지하면서 초소형 RF 전치단을 실현하기 위한 능동소자와 안테나가 결합하여 복합 기능을 하는 능동 집적 안테나(AIA, Active Integrated Antenna) 기술 현황, RF 시스템 단일 패키지(RF-SOP, System On Package) 형태에 집적 가능한 안테나 및 미래의 꿈인 RF 시스템 단일 칩 (RF-SOC, System On Chip)을 향한 단일 칩 안테나 (AOC, antenna on chip) 기술 동향 등이 기술된다.

• Journal of IKEEE
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• v.17 no.2
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• pp.163-167
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• 2013

As the mobile services have been increased, the interference of the neighboring base stations is increased and the PIMD(Passive Inter-Modulation Distortion) has been a main issue for the design of base station antenna systems. In this paper, it is proposed the PIMD test method for the active basestation antenna whose radiators are directly connected with main active parts including amplifiers, and we presents its test results using a developed active basestation antenna. From the results, the active basestation antenna has the better PIMD performance than conventional passive structure by 8.4dB. The proposed PIMD test method can be used to get the accurate PIMD test result because the test environment is very similar with real basestation.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.3
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• pp.43-49
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• 2008

The Real Time Location System (RTLS) is very important in the ubiquitous society for real time tracking of men, high price assets, and logistics products. In this work, we developed an active RF system for RTLS and tested its performance. The RTLS system developed in this work was constructed of three active readers and one active tag. The small size tag developed in this work operated with a coin type battery. To make the tag smaller, we used an internal PCB antenna and a chip antenna. We tested the performance of the tag. To reduce the manufacturing cost of our RF system, we used low price RF transceiver CC2510 chip-set. The CC2510 chip-set provided RSSI(Received Signal Strength Indicator) signal which could be used to determine the distances between an active tag and three active readers.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.5
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• pp.46-51
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• 2013

In this paper, a dual-band antenna is proposed for the RF power harvester system as well as RFID tag. The proposed antenna operates as the passive and active RFID tag antenna in the UHF and microwave band, respectively. In addition, to charge the battery of an active RFID tag in the microwave band, it harvest the RF signal for tagging from the passive RFID tag antenna in the UHF band. The proposed antenna operates in the UHF band (917~923.5 MHz) and microwave band (2.4~2.45 GHz). In order to obtain the dual-band operation, the dipole structure and meander parasitic elements are proposed as the ${\lambda}/2$ and $1{\lambda}$ dipole antenna, respectively. The radiating dipole structure in the microwave band acts as the coupled feed for the meander parasitic elements in the UHF band. The impedance bandwidth (VSWR < 2) of the proposed antenna covers 917~923.5 MHz (UHF band) and 2.4~2.45 GHz (Microwave band). Measured total efficiencies are over 45 % in the UHF band and over 70 % in the microwave band. Peak gains are over 0.18 dBi and 2.8 dBi in the UHF and microwave band with an omni-directional radiation pattern, respectively.

• Electronics and Telecommunications Trends
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• v.23 no.3
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• pp.138-143
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• 2008

우리는 전파를 기반으로 하는 유비쿼터스 통신 시대를 향해 살고 있다. 새로운 통신 시대를 꿈꾸며 살아가는 현대인은 거의 매일 무선 통신을 이용하고 있으며 그것을 가능케 하는 안테나 기술은 눈부시게 발전하고 있다. 그러나 요즘처럼 무선 통신 서비스가 다양해지고 전파가 전파(propagation)되는 환경은 열악해지고 있는 상황에서 무선통신의 품질은 안테나의 성능에 좌우된다. 또한 통신방송융합서비스가 가시화되면서 더욱 성능이 우수한 안테나 모델을 개발하기 위해 다양한 기술적 접근이 시도되고 있다. 본 기고에서는 지상파 DMB 단말기로 대표되는 통방융합 무선통신 단말기에 적합한 소형 안테나 기술, RF 및 밀리미터파 시스템의 소형화, 고효율화, 집적화 추세에 따른 능동형 안테나 기술, 소형화된 다중대역 안테나 기술, 그리고 신소재 응용 안테나에서 재구성 안테나 기술까지 다양한 안테나 기술의 동향을 살펴보고자 한다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.2
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• pp.72-78
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• 2021

This paper proposes a wide-band dual-polarization stacked patch array antenna for satellite SAR system applications. The array antenna was designed for loss minimization and wide-band characteristics to enhance the performance of the SAR system and optimize it for active return loss in applications to active phased arrays. The fabricated array antenna showed a performance of 19.26%/19.79% fractional bandwidth within the -10 dB reference level of the active return loss and showed loss characteristics of 0.797 dB/0.799 dB averaged within the operational frequency for both H/V-polarization cases. The pattern performance was verified by comparing the measured patterns with the calculated patterns obtained by the array factor.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.23-30
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• 2022

The active phased array antenna system performs beam steering, multi-beam formation and adaptive beam forming by controlling the amplitude and phase of signals fed to each radiating element. In order to obtain the desired radiation characteristics using an active phased array antenna system, the accurate amplitude and phase of the signal must be fed to each radiating element; however, due to various causes, the signal errors occurs in each radiating element. In this paper, a signal error estimation method of each radiating element is proposed. The proposed method simplifies the process of signal error estimation, and can quickly and accurately calculate the signal error.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.955-964
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• 2010

In this paper, a compensation method of the amplitude and phase errors from the T/R(Transmit/Receive) modules in an active SAR(Synthetic Aperture Radar) system is introduced. The errors are defined and classified, and characterized by analyzing the measurement data acquired from the pilot test. To compensate these errors, a control methodology of T/R modules output is proposed. Before the compensation is applied, 16 T/R modules integrated on the active SAR antenna show the amplitude in 28.2~29.0 dBm and the phase in $101.7^{\circ}{\sim}165.2^{\circ}$. After the compensation, the amplitude and phase are distributed in 27.4~28.0 dBm and $116.1^{\circ}{\sim}120.0^{\circ}$ respectively. The antenna beam patterns generated by the array theory with the distributions are compared, and the proposed method is verified as good to apply for the active SAR system.

• Journal of Korean Society for Geospatial Information Science
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• v.17 no.1
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• pp.113-120
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• 2009

Through the automatic sensing of the environment, USN technology can give the best services. In this work, we have developed an active RFID system and examined its performance. By implementing it into water quality sensors, we constructed a system that can detect diverse indoor/outdoor environment and provide information about the pollution level obtained from the temperature and PH sensors. Our RF system had an internal Print-on-PCB antenna for the miniaturization of the tag. We used a RF transceiver CC2510 chipset of TI company to realize the active RFID function. By using RSSI constants obtained, we performed the evaluation of real time location accuracy with a software written in Labview. Among 10 arbitrary locations, we obtained average measurement errors of 1.69 m in x axis and 1.66 m in y axis. This technology can be applied to logistics, environmental monitoring, prevention of missing children and various applications.