• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.713-715
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• 2012

본 논문은 24GHz 차량 추돌 예방 레이더 시스템-온-칩을 위한 입력 임피던스, 전압이득 및 잡음지수를 자동으로 측정할 수 있는 새로운 형태의 고주파 자체 내부검사(BIST, Built-In Self-Test) 회로를 제안한다. 이러한 BIST 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정 ($f_T/f_{MAX}$=140/120GHz)으로 설계되어 있다. 알고리즘은 LabVIEW로 구현되어 있다. BIST 알고리즘은 입력 임피던스 정합과 출력 직류 전압 측정원리를 이용한다. 본 논문에서 제안하는 방법은 자동으로 쉽게 고주파 회로의 성능변수를 측정할 수 있기 때문에 시스템-온-칩의 저가 성능 검사의 대안이 될 것으로 기대한다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.8 no.1
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• pp.29-37
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• 1997

CW나 pluse의 형태로 RF를 발진하는 고출력 전자파 발진기는 레이더 체계의 기본요소이다. 레이더 체계의 성공적인 운행을 위한 요건 중에 적합한 전자파 발진기의 선택과 개발을 무시할 수 없다. 이차세계대전을 전후로 활발히 개발되었던 전자파 발진기들 중에는 널리 알려진 Magnetron과 klystron 이 있고 TWT(traveling wave tube)도 그 후 널리 사용되는 발진기이다. 지난 반세기를 지나오며 성능 및 신뢰도 등에서 괄목할만한 발전을 이루었으며 밀리미터파대역의 고출력 발진을 위해 gyrotron 등이 지난 30년간 개발되었다. 현재는 성능, 크기(무게) 및 가격의 문제뿐 아니라 고정밀 영상을 위한 고주파 발진기의 개발이 추진되고 있다. 여기서는 현재 레이더에 쓰이고 있는 magnetron, klystron, TWT 및 gyrotron에 대한 간략한 배경, 원리 및 특성 등을 비교 설명하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.6
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• pp.198-210
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• 2022

The southern strait of Jeju is a divergence point of the Tsushima Warm Current (TWC), and it is the starting point of the thermohaline circulation in the waters of the Korean Peninsula, affecting the size and frequency of marine disasters such as typhoons and tsunamis, and has a very important oceanographic impact, such as becoming a source of harmful organisms and radioactively contaminated water. Therefore, for an immediate response to these maritime disasters, real-time ocean observation is required. However, compared to other straits, in the case of southern Jeju, such wide area marine observations are insufficient. Therefore, in this study, surface current field of the southern strait of Jeju was calculated using High-Frequency radar (HF radar). the large surface current field is calculated, and post-processing and data improvement are carried out through APM (Antenna Pattern Measurement) and FOL (First Order Line), and comparative analysis is conducted using actual data. As a result, the correlation shows improvement of 0.4~0.7 and RMSE of about 1~19 cm/s. These high-frequency radar observation results will help solve domestic issues such as response to typhoons, verification of numerical models, utilization of wide area wave data, and ocean search and rescue in the future through the establishment of an open data network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.760-761
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• 2013

본 논문은 차량 추돌 예방 레이더용 24GHz 전압제어발진기를 제안한다. 이러한 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정($f_T/f_{MAX}=120/140GHz$)으로 설계되어 있다. 이러한 회로는 스위치형 공진기 (switched resonator)의 기본 구조를 지닌 24GHz 주파수 대역을 사용할 수 있도록 CMOS LC 튜닝 회로를 포함하고 있다. 특히 전체 칩 면적을 줄이기 위해 수동형 인덕터 대신 능동형 인덕터부를 사용하였다. 본 연구에서 개발한 발진기는 전체 튜닝 범위에 대해 24GHz에서 8%의 측정결과를 보였으며, 600kHz 오프셋에서 24GHz에 대해 약 -89dBc/Hz의 우수한 위상 잡음 특성을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.702-703
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• 2013

본 논문은 차량 추돌 예방 레이더용 24GHz 전압제어발진기를 제안한다. 이러한 회로는 TSMC $0.13{\mu}m$ 혼성신호/고주파 CMOS 공정($f_T/f_{MAX}=120/140GHz$)으로 설계되어 있다. 이러한 회로는 스위치형 공진기 (switched resonator)의 기본 구조를 지닌 24GHz 주파수 대역을 사용할 수 있도록 CMOS LC 튜닝 회로를 포함하고 있다. 특히 전체 칩 면적을 줄이기 위해 수동형 인덕터 대신 능동형 인덕터부를 사용하였다. 본 연구에서 개발한 발진기는 전체 튜닝 범위에 대해 24GHz에서 8%의 측정 결과를 보였으며, 600kHz 오프셋에서 24GHz에 대해 약 -89dBc/Hz의 우수한 위상 잡음 특성을 보였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.10
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• pp.1386-1391
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• 2018

The radar in the moving platform is interfered by the mainlobe clutter as well as the altitude clutter that is received from sidelobe. The altitude clutter is relatively short range compared to mainlobe clutter and therefore enters the radar with a strong signal. As these clutters are major reason making the probability of false alarm high, it is required to suppress both altitude clutter and mainlobe clutter. In this paper, It is proposed the clutter suppression method consisted of two pulse canceller to suppress the clutters being two frequency area in moving platform. It is analyzed the correlation of output signals according to the use of pulse canceller and provided the structure of staggered pulse canceller considered the correlation. Finally, it shows that altitude clutter and mainlobe clutter are suppressed by proposed staggered pulse canceller using the simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.425-432
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• 2014

Necessity of compact X-band solid-state weather radar is required to provide weather data, which generate locally in a lot of Korea's mountainous area, rather than tube-type radar. Solid State Power Amplifier (SSPA) for using Dual-polarization method in weather radar is able to obtain desired high output by combining many low output power devices in parallel. Thus, Power combiner applying to high-output power amplifier has disadvantages such as path loss, ballast resistance problem by high frequency and high power, heat release. Therefore, In this paper we demonstrated the excellence of isolation, which is the result from modified Gysel power combiner. As a result, we designed X-band 250W solid state power amplifier with peak power 54dBm, 25% power efficiency for weather radar.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.558-565
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• 2013

In this paper, modeling and simulation for performance analysis of high resolution SAR system has been carried out in the time, frequency and numeric domain using ADS Ptolemy simulation tool of Agilent corporation. SAR system consists of antenna, controller and transceiver. Error parameters affecting SAR system performances have been defined, modeled and simulated such as phase noise of frequency synthesizer, amplitude and phase characteristic of TWTA, sampling frequency of waveform generator and I/Q imbalance. Finally, the development requirements of SAR system based on the impulse response function have been derived.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.187-196
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• 2009

Synthetic Aperture Radar(SAR) satellite system for broad-area imaging has RF systems including SAR radiating a high power, data link system transmitting the acquired image data from the SAR, TC&R(Telemetry, Command, and Ranging) to communicate with a ground segment to control a satellite. Each system transmits RF signal having various frequencies and radiates a high power, RS(Radiated Susceptibility) specification should be verified at an electronic unit mounted in satellite. RF interference can be happened because of non-linearity of a RF system. Therefore, we manufactured a structure model installed antennas which have a similar pattern with a real antenna, the effect by RF interference is analyzed and verified.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.4
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• pp.331-339
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• 2010

To analyze and verify the performance of a MWR(Missile Warning Radar) of a GVWS(Ground Vehicle Weapon System), there is a need to make a simulator which can conduct the linked and engaged test virtually using the simulated signals. In this paper, a method of the simulator design for MWR is proposed to solve the above need. The SP(Signal Processor) part which generates the simulated signals and analyzes the algorithms is explained. The RF(Radio Frequency) part which transforms IF(Intermediate Frequency) signals into RF signals, radiates RF signals, and controls the linked equipments is also explained. The utility of the proposed design is proved by presenting the results of the contributions to the development of MWR.