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Drone-Based External Calibration of a Fully Synchronized Ku-Band Heterodyne FMCW Radar
Jun-Seuk Suh,Minz, Laxmikant,Dae-Hwan Jung,Hyun-Seong Kang,Jong-Wook Ham,Seong-Ook Park IEEE 2017 IEEE transactions on instrumentation and measureme Vol.66 No.8
<P>This paper discusses a novel drone-based external radar calibration technique, which utilizes a metal sphere hanging from a drone. The advantages of drone-based calibration are introduced and applied to a dual intermediate-frequency frequency-modulation continuous-wave (FMCW) radar system, which was developed to detect a low radar cross section (RCS) target like a drone with high sensitivity. The developed radar system operates in 150-MHz bandwidth with a frequency sweeping time of 500 μm at Ku-band frequencies. A 75-Ω coaxial cable was utilized in the radar system to physically separate the transmitter (Tx) and receiver (Rx) modules for better isolation. The physical separation with a coaxial cable helps in reducing Tx leakage signal effect, which is a critical concern of typical FMCW radar system, and also it helps the proposed radar system to have higher sensitivity. The designed radar system is a wired system that is fully synchronized with an internal reference clock generator. Offset frequency and other compensation factors were calculated for the calibration of the radar system using a big size metal sphere hanging from a drone. We observed that the theoretical calculations using the standard radar equation and the measurement results on calibration are in good agreement with each other. Furthermore, the RCS value of a small size drone is also investigated using the calibrated radar system. The RCS value estimated for the drone was about -22 dBsm.</P>
유방암 진단 시스템을 위한 정합 액체의 전파 특성에 관한 연구
김장렬(Jang-Yeol Kim),Minz Laxmikant,이광재(Kwang-Jae Lee),손성호(Seong-Ho Son),전순익(Soon-Ik Jeon) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.4
본 논문은 피부를 포함하는 유방 모델에서 정합 액체의 전파 특성에 관한 연구 내용이다. 정합 액체의 분석을 위해 6개 타입의 정합 액체를 제안된 1-D 유방 모델에 적용하여 3~6 GHz의 주파수 대역에서 분석 연구를 수행하였다. 균일한 평면파가 1-D 유방 모델 내부의 복합 매질의 경계면에 입사되어 반사/투과되어 나타나는 전파 특성과 각 정합 액체의 전송 선로 손실을 분석하였다. 본 논문에서 연구한 방법은 유방암 진단 시스템, 인체 조직을 이용한 암 진단 분야 및 기타 의료기기 분야에 활용될 수 있으며, 본 논문에서는 유방암 진단 시스템에 적용하였다. 본 연구는 향후 유방암 진단시스템에 적용될 적절한 정합 액체를 선정하고, 성능을 분석하는데 유용하게 적용될 수 있다. This paper is a study of the propagation characteristic of matching liquids in the skin-covered breast model. In order to evaluate the matching liquids, we investigated six kinds of matching liquids applied to proposed 1-D breast model from frequency range of 3 ~6 GHz. A uniform plane wave is projected / transmitted inside the multi-layered breast model. Then the propagation characteristics inside the model and the transmission loss of each matching liquids were analyzed. The studying method presented in the paper can be used in the breast cancer detection system, the field of cancer detection using human tissue and the field of other medical devices. This paper was applied to the breast cancer detection system. Consequently, these studies could be used to determine the suitable type of matching liquids for breast cancer detection system and to apply useful for performance analysis.
Compact Broadband Microstrip Crossover With Isolation Improvement and Phase Compensation
Soon Young Eom,Batgerel, Ariunzaya,Minz, Laxmikant IEEE 2014 IEEE microwave and wireless components letters Vol.24 No.7
<P>In this letter, we present a broadband microstrip crossover structure in two different configurations. Both structures have compact size, i.e., less than 10 mm × 10 mm. Across the measured band from dc to 10 GHz, the structure 1 has less than 1 dB insertion loss, more than 20 dB return loss and at least 23.3 dB isolation. Within the same band, the structure 2 has less than 1 dB insertion loss, more than 22 dB return loss and at least 18.9 dB isolation. Phase difference between two paths in both structures is kept in less than 5 <SUP>°</SUP>.</P>
Park, Seong-Jin,Jeong, Myung-Hun,Bae, Kyung-Bin,Kim, Dong-Chan,Minz, Laxmikant,Park, Seong-Ook Institute of Electrical and Electronics Engineers 2017 IEEE transactions on antennas and propagation Vol.65 No.12
<P>A performance comparison of <TEX>$2 \times 2$</TEX> multiple-input multiple-output (MIMO) antenna arrays with different configurations and polarizations in a reverberation chamber (RC) is presented at the 28-GHz band. Eight types of antenna arrays are proposed according to different configurations and polarizations. The measured results of the antenna arrays show that they have similar antenna performance with respect to the same array size except for those concerning with the polarization. Based on these antenna arrays, we propose twelve cases of <TEX>$2 \times 2$</TEX> MIMO antenna arrays with dual-separated polarizations between top and bottom side. A 28-GHz channel sounder and a vector network analyzer were used to measure complex channel transfer functions at the specific position of the rotating mode stirrer in the RC. The proposed MIMO antenna arrays were measured in the RC without and with absorbers. To clarify the channel performance for each case, a wideband channel capacity is calculated from the measured result.</P>