• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.410-418
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• 2000

In this paper, path losses in millimeter-wave band for different propagation environments are measured, and the results are analyzed by modeling the median, maximum, and minimum values of the measurement data for each site, which are recorded for 5 minutes, with a linear regression model. The measurement data shows that in urban and suburban environments, extra path loss must be taken into account for line-of-sight path, even in millimeter wave band.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.7
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• pp.3050-3065
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• 2016

Neural networks (NNs) are extensively used in applications requiring signal classification and regression analysis. In this paper, a NN based threshold selection algorithm for 60 GHz millimeter wave (MMW) time of arrival (TOA) estimation using an energy detector (ED) is proposed which is based on the skewness, kurtosis, and curl of the received energy block values. The best normalized threshold for a given signal-to-noise ratio (SNR) is determined, and the influence of the integration period and channel on the performance is investigated. Results are presented which show that the proposed NN based algorithm provides superior precision and better robustness than other ED based algorithms over a wide range of SNR values. Further, it is independent of the integration period and channel model.

• ETRI Journal
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• v.24 no.3
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• pp.190-196
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• 2002

This paper presents millimeter wave monolithic microwave integrated circuit (MMIC) low noise amplifiers using a $0.15{\mu}m$ commercial pHEMT process. After carefully investigating design considerations for millimeter-wave applications, with emphasis on the active device model and electomagnetic (EM) simulation, we designed two single-ended low noise amplifiers, one for Q-band and one for V-band. The Q-band two stage amplifier showed an average noise figure of 2.2 dB with an 18.3 dB average gain at 44 GHz. The V-band two stage amplifier showed an average noise figure of 2.9 dB with a 14.7 dB average gain at 65 GHz. Our design technique and model demonstrates good agreement between measured and predicted results. Compared with the published data, this work also presents state-of-the-art performance in terms of the gain and noise figure.

• Journal of electromagnetic engineering and science
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• v.10 no.4
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• pp.322-327
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• 2010

Spaceborne sparse array radar for ground moving targets indication (GMTI) has outstanding advantage over full array radar for constructing ultra-large aperture. Rapid development of millimeter wave (MMW) technology make it possible for realizing MMW GMTI radar, which is much more sensitive to slow moving ground target. The paper presented the system model of a multi-carrier frequency sparse array MMW radar as well as preliminary simulation results, which showed future application of the system is very promising.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1022-1024
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• 2009

Stereoscopic Images provide depth information with the relative distances between the objects in the images. There are many different ways to extract disparity maps from the visible spectral images. For the infrared spectral range, the same approach cannot be utilized for the innate low resolution and colorless features because typical methods require corresponding features between the images. The authors suggest a new approach that makes use of image segmentation to obtain depth information for stereoscopic millimeter-wave images. For image segmentation a selective visual attention model based on the theory of a feature-integration of attention is used. Experimental results show the proposed method provides reasonable depth information for object shape recognition and display.

• Journal of IKEEE
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• v.16 no.2
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• pp.127-130
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• 2012

In this paper, we reported on a single balanced monolithic diode mixer using Marchand balun for millimeter-wave applications. The single balanced monolithic mixer was fabricated using drain-source-connected pseudomorphic high electron mobility transistor (PHEMT) diodes considering the PHEMT MMIC full process. The average conversion loss is 16 dB in the RF frequency range of 81~86 GHz at LO frequency of 75 GHz with LO power of 10 dBm. The RF-to-LO isolation characteristics are greater than -30 dB and the total chip size is $1.0mm{\times}1.35mm$.

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

Technologies for high-speed transistors, active devices essential to the fabrication of millimeter wave circuits have developed drastically with the design and processing techniques. The high frequency transistors, made of GaAs or InP related compound semiconductors mainly, are in the form of MODFETs and HBTs. Other than traditional III-V compound semiconductor materials, SiGe and GaN technologies are emerging as viable candidates of millimeter-wave devices. In this paper, basis and applications of millimeter-wave transistors are introduced.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.603-606
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• 2006

In this study, we proposed a Modified Log-Periodic Tooth antenna structure with reflector for millimeter wave image sensor of PMMW(Passive Millimeter Wave). PMMW image sensor satisfy the requirements, such as, High Gain, Wideband, and Planar antenna structure.

• International journal of advanced smart convergence
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• v.9 no.4
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• pp.156-166
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• 2020

In this paper, to improve spectral efficiency and mitigate interference in coordinated millimeter-wave systems, we proposes an optimal user group and beam selection scheme. The proposed scheme improves spectral efficiency by mitigating intra- and inter-cell interferences (ICI). By examining the effective channel capacity for all possible user combinations, user combinations and beams with minimized ICI can be selected. However, implementing this in a dense environment of cells and users requires highly complex computational abilities, which we have investigated applying multiclass classifiers based on machine learning. Compared with the conventional scheme, the numerical results show that our proposed scheme can achieve near-optimal performance, making it an attractive option for these systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.8
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• pp.890-895
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• 2016

As the wireless communication technique is developing rapidly, the use of smart devices is increasing. Due to gradually increasing data traffic, a new area, more than 6GHz of bandwidth to increase capacity of the network, has been studied. Millimeter Wave(MmWave) communications utilizes the bandwidth above 6GHz, which makes it possible to achieve one gigabit per second data rate. To overcome the path loss due to the smaller wavelength, the mass of the antenna arrangement is used. This paper presents an algorithm that maximizes the spectral efficiency of the system in the pre-coding process using a hybrid beamforming. Also it is suggested with the optimization of the number of beams that maximizes the spectral efficiency was maximized by the propose method.