• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.52-62
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• 2000

이동통신의 발달로 가속화된 고주파 반도체 소자 기술 중 새로운 가능성을 가진 밀리미터파 대역의 주요 응용분야와 이를 위한 부품기술을 살펴보았다. 부품기술로는 LG종합기술원에서 개발된 최근의 결과들을 소개하면서 공정기술, 소자기술, 회로설계기술, 조립기술에 대해 알아보았다. 공정기술과 소자기술은 밀리미터파에서 주로 사용되는 HBT와 HEMT를 기준으로 살펴보고 회로설계기술은 기존의 GHz 대역의 설계기술과 밀리미터파 회로 설계기술의 차이점을 언급하였다. 조립기술에 대해서는 일반적으로 MMIC 회로를 제작할 때 사용하는 마이크로스트립 전송선로를 밀리미터파 응용에서 주로 이용하는 도파관에 연결하기 위한 변환구조를 중심으로 설명하였다. 또한 국내외 타 기관에서 이루어지고 있는 이 분야에 대한 기술개발 노력과 연구동향에 대해서도 간단히 알아보았다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.3
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• pp.529-534
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• 2004

Millimeter waves are potentially useful for high resolution ranging and imaging in low optical visibility conditions such as fog and smoke. Also, They are used for wide band communications. However, it is necessary to develop a theoretical and experimental understanding of millimeter wave propagation to assess the performance of millimeter wave systems. The intensity fluctuations and mutual coherence function (MCF) describe atmospheric effects on the millimeter wave propagation. Using the quasi-optical method (QOM), an efficient and practical method was suggested to obtain the intensity distribution of the antenna focal plane from MCF which can be determined using meteorological data.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.7
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• pp.1581-1587
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• 2004

In this paper, We have proposed an Heterodyne technique to generate millimeter-wave signal. Microwave signals in cellular broadband mobile communication networks and distributed networks can favorably be generated and distributed by optical techniques. In principle, these techniques have already been investigated for optical control of phase-array antennas, characterization of photo-detector and phase locking of millimeter-wave oscillators and now being applied to wireless communications. The generation and transmission of millimeter-wave radio signals by optical means is of interest for future pico-cell broadband mobile communication system, especially for systems operating at frequencies of 300Hz.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2769-2774
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• 2010

In this paper, we have proposed sideband injection locking method, heterodyne technique, to generate millimeter-wave signal. Microwave signals in cellular broadband mobile communication networks and distributed networks can favorably be generated and distributed by optical techniques. In principle, these techniques have already been investigated for optical control of phase-array antennas, characterization of photo-detector and phase locking of millimeter-wave oscillators and now being applied to wireless communications. The generation and transmission of millimeter-wave radio signals by optical means is of interest for future pico-cell broadband mobile communication system, especially for systems operating at frequencies of tens of GHz applicable to LMDS. We experimented and analysed the generation of millimeter wave signal.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.133-138
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• 2008

A 50-60GHz continuous-wave(cw) millimeter-wave(MMW) was converted(generated) by applying optical technology for future wireless and ubiquitous communications. The optical power of 22.5mW was injected into optical waveguide in this experiment. The generated MMW signals were radiated in a millimeter waveguide and detected through a millimeter detector on the inside of a millimeter waveguide in this experiment. The spectral linewidth of the MMW signals was less than 1 kHz. The power fluctuation of the MMW was less than 1.2 dBm over 50-60 GHz range.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.1
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• pp.21-24
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• 2017

Passive millimeter wave (MMW) imaging penetrates clothing to detect concealed objects. The distances extraction to the concealed objects is critical for the security and defense. In this paper, we address a passive stereo 3 mm MMW imaging system to extract the longitudinal distance to the concealed object. The concealed object area is segmented and extracted by the k-means clustering algorithm with splitting initialization. The distance to the concealed object is estimated by the corresponding centers of the segmented objects. In the experimental two pairs (each pair for horizontal and vertical polarization) of stereo MMW images are obtained to estimate distances to concealed objects.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.3 s.357
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• pp.111-116
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• 2007

We have developed a passive millimeter wave (PMMW) imaging system with two-dimensional imaging arrays. For the imaging system we achieved single-substrate imaging-array element which include all necessary component such as Fermi tapered slot antenna (TSA), a balun, LNA's and a detector circuit on it. Two-dimensional arrays for real-time imaging at the 35 GHz band are currently under development. We will be able to make an advanced PMMW image system based on our system with the $2\times2$ imaging array in the near future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.2C
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• pp.181-187
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• 2012

Millimeter wave (MMW) readily penetrates fabrics, thus it can be used to detect objects concealed under clothing. A passive MMW imaging system can operate as a stand-off type sensor that scans people in both indoors and outdoors. However, because of the diffraction limit and low signal level, the imaging system often suffers from low image quality. Therefore, suitable statistical analysis and computational processing would be required for automatic analysis of the images. In this paper, a real-time concealed object detection is addressed by means of the multi-level segmentation. The histogram of the image is modeled with a Gaussian mixture distribution, and hidden object areas are segmented by a multi-level scheme involving $k$-means, the expectation-maximization algorithm, and a decision rule. The complete algorithm has been implemented in C++ environments on a standard computer for a real-time process. Experimental and simulation results confirm that the implemented system can achieve the real-time detection of concealed objects.

• Food Engineering Progress
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• v.21 no.2
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• pp.126-131
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• 2017

Millimeter waves are electromagnetic waves with frequencies of 30-300 GHz (wavelength 1-10 mm), and millimeter wave stimulation affects microorganism growth. The present study stimulated Bacillus subtilis with 60 and 70 GHz millimeter waves during cheonggukjang fermentation and characterized the effects on cheonggukjang quality. Cheonggukjang treated with millimeter wave irradiation showed no significant difference in total bacterial count but generated only 5.52-5.92% viscous substance. Irradiation with 60 GHz millimeter waves yielded bright and intense color values relative to 70 GHz millimeter waves. Examination of the amylase activity and reducing sugar content of finished cheonggukjang revealed that irradiation at 70 GHz inhibited amylase activity in cheonggukjang. Furthermore, irradiation at 70 GHz increased protease activity, whereas irradiation at 60 GHz inhibited the activity. Moreover, the amino acid content changed with millimeter wave irradiation.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.59-67
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• 1998