• Journal of electromagnetic engineering and science
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• v.13 no.4
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• pp.214-223
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• 2013

This paper proposes a theoretical analysis of hidden device detection and a design of multiband circular polarization patch array antenna for non-linear junction detector system application. A good axial ratio of circular polarization patch antenna is realized by a new approach that employs inclined slots, two rectangular grooves and a truncated ground for the conventional antenna. A good axial ratio of the 1.5 dB lower is measured by having an asymmetric gap distance between the ground planes of the coplanar waveguide feeding structure. The common ground plane of the linear array has an optimum trapezoidal slot array to reduce the mutual coupling without increasing the distance between the radiators. The higher gain of about 1 dBi is realized by using the novel common ground structure. The measured return loss, gain, and axial ratio of the proposed single radiator, as well as the proposed array antennas, showed a good agreement with the simulated results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.648-653
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• 2011

We propose a new frequency offset estimation technique for multiband orthogonal frequency modulation (MB-OFDM) based ultra wideband (UWB) systems. The proposed frequency offset estimation technique is related to the scheme of Schmidl for channel model 1 (4-1Om NLOS, rms. delay =14.3ns.) using more than two symbols and with alternate symbols. Variance of frequency offset estimate obtained from the proposed frequency offset estimation technique approaches very nearing to Cramer Rao Lower Bound (CRLB) in an AWGN channel. BER performance of the proposed technique is also presented.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2286-2292
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• 2008

In this paper, we design a RS(23,17) decoder for MB-OFDM(Multiband-Orthogonal Frequency Division Multiplexing) system, in which Modified Euclidean(ME) algorithm is adopted for key equation solver block. The proposed decoder has been optimized for MB-OFDM system so that it has less latency and hardware complexity. Additionally, we have implemented the proposed decoder using Verilog HDL and synthesized with Samsung 65nm library. From synthesis results, it can operate at clock frequency of 250MHz, and gate count is 20,710.

• Korean Journal of Remote Sensing
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• v.17 no.4
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• pp.335-344
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• 2001

Texture is extensively studied in a variety of image processing applications such as image segmentation and classification because it is an important property to perceive regions and surfaces. This paper focused on the analysis and synthesis of textured single and multiband images using Markov Random Field model considering the existent spatial correlation. Especially, for multiband images, the cross-channel correlation existing between bands as well as the spatial correlation within band should be considered in the model. Although a local interaction is assumed between the specified neighboring pixels in MRF models, during the maximization process, short-term correlations among neighboring pixels develop into long-term correlations. This result in exhibiting phase transition. In this research, the role of temperature to obtain the most probable state during the sampling procedure in discrete Markov Random Fields and the stopping rule were also studied.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.110-115
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• 2021

A multi-band, compact, and complex vehicle roof antenna has become important in terms of car exterior design and multi-functions which include Radio, DAB/DMB, SXM, GNSS, Telematics, and V2X. In this paper, we propose a compact multi-band V2X pole-type roof antenna. Using impedance change characteristic, a single pole antenna which has multiband such as radio, DAB/DMB, telematics, and V2X band is proposed. With two patch antennas for GNSS and SXM, the dimension of a multiband roof antenna is 131x63x37mm only.

• 한국ITS학회:학술대회논문집
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• 2004.11a
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• pp.236-240
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• 2004

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1645-1653
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• 2014

In general, RGB, NIR, and thermal images are used for obtaining geospatial data. Such multiband images are collected via devices mounted on satellites or manned flights, but do not always meet users' expectations, due to issues associated with temporal resolution, costs, spatial resolution, and effects of clouds. We believe high-resolution, multiband images can be obtained at desired time points and intervals, by developing a payload suitable for a low-altitude, auto-piloted UAV. To achieve this, this study first established a low-cost, high-resolution multiband image collection system through developing a sensor and a payload, and collected geo-referencing data, as well as RGB, NIR and thermal images by using the system. We were able to obtain a 0.181m horizontal deviation and 0.203m vertical deviation, after analyzing the positional accuracy of points based on ortho mosaic images using the collected RGB images. Since this meets the required level of spatial accuracy that allows production of maps at a scale of 1:1,000~5,000 and also remote sensing over small areas, we successfully validated that the payload was highly utilizable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.11C
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• pp.694-701
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• 2011

This paper addresses a synchronization technique based on an adaptive combining of the sub-correlation functions obtained from multiband sine phased binary offset carrier (BOC) signals, allowing a BOC signal receiver to deal with multiband sine phased BOC signals. Specifically, we first obtain the sub-correlation functions composing the BOC autocorrelation function, and then, re-combine the sub-correlation functions generating a correlation function with no side-peak. Finally, by replacing the BOC autocorrelation with the correlation function with no side-peak in the delay lock loop, the proposed scheme performs unambiguous signal tracking. The proposed synchronization scheme is applicable to generic sine phased BOC signals. Numerical results demonstrate that the proposed scheme provides a performance improvement over the conventional unambiguous schemes in terms of the tracking error standard deviation.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.6
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• pp.231-237
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• 2016

This paper presents a multiband low phase noise CMOS VCO with wide frequency tunability using switched bondwire inductor bank. The combination of bondwire inductor and CMOS switch transistor enhances frequency tunability and improves phase noise characteristics. The proposed multiband VCO operates from 2.3GHz to 6.3GHz with phase noise of -136dBc/Hz and -122dBc/Hz at 1 MHz offset frequency, respectively. Switched bondwire inductor bank shows high quality factor(Q) at each frequency band, which allows better tradeoff between phase noise and power consumption. The proposed VCO is designed in TSMC 0.18um CMOS process and consumes 7.2 mW power resulting in figure of merit(FOM) of -189.3dBc/Hz at 1 MHz offset from 6GHz carrier frequency.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.11
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• pp.91-96
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• 2010

In this paper, an internal USB dongle antenna with a circular hook-shaped patch is proposed. The proposed antenna comprises of a circular hook-shaped patch and a monopole stub. The proposed antenna with the dimension of $10mm{\times}50mm{\times}0.8mm$ was fabricated on commercial FR-4 substrate with a dielectric constant of 4.6 and tangent loss of 0.025. The designed antenna exhibits three different resonant bandwidths, 2.4 GHz-2.5 GHz, 3.4 GHz-3.6 GHz, and 5.15 GHz-5.825 GHz. The measured radiation patterns are omni-directional at measured frequencies. Therefore, the proposed antenna is suitable for wireless USB dongle antenna that can support multiband wireless services such as WLAN, WiMAX and Bluetooth.