• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2457-2462
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• 2010

In this paper, We applied CCI canceller to remove multiple access interference in co-channel environment and improved performance of Impulse Radio UWB system. Also, we have evaluated the performance of UWB system with Truncated Type-II Hybrid ARQ scheme for achieving high quality data transmission.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.220-226
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• 2004

Ultra-wideband(UWB) communication applications is a recent innovation due to high transmission rate and low power emission. Therefore, it is important to research UWB signal's characteristics and modulation methods to apply to various UWB communication technologies. In this paper the characteristics of Gaussian monopulse which is capable of using UWB communication was analyzed and we compared the performance of PPM and PAM modulation method. Also we analyzed the interference effect of QPSK system with different center frequencies in the present of various UWB noises and simulated simple UWB transceiver system.

• ETRI Journal
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• v.27 no.5
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• pp.579-584
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• 2005

A CMOS direct-conversion mixer with a single transistor-level topology is proposed in this paper. Since the single transistor-level topology needs smaller supply voltage than the conventional Gilbert-cell topology, the proposed mixer structure is suitable for a low power and highly integrated RF system-on-a-chip (SoC). The proposed direct-conversion mixer is designed for the multi-band ultra-wideband (UWB) system covering from 3 to 7 GHz. The conversion gain and input P1dB of the mixer are about 3 dB and -10 dBm, respectively, with multi-band RF signals. The mixer consumes 4.3 mA under a 1.8 V supply voltage.

• Journal of Advanced Navigation Technology
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• v.13 no.4
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• pp.515-522
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• 2009

In this paper, we have investigated the technology of location-aware applicable for ubiquitous environment and considered IEEE 802.15.4a IR UWB of location-aware WPAN specification which is capable of both communication of 1Mbps and wireless localization. We analyzed both system structure and the characteristic of transmission pulse as comprising of the transmitter for wireless localization of IR UWB.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.59.2-59.2
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• 2016

As an enhancement to increase mapping speed of the current ALMA TP array, development of a focal plane array system working at ultra wide frequency range of 275-500 GHz with GPU-based software spectrometers has been carried out since 2015. Major progresses on such component development as wideband DSB mixers, a profiled corrugated horn, receiver optics, LO system and GPU-based spectrometer are reviewed with brief introduction to implication of ALMA 2030 for technical implementation.

• ETRI Journal
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• v.28 no.1
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• pp.91-94
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• 2006

Impulse radio (IR) is a competitive candidate for ultra-wideband (UWB) systems. In this letter, we evaluated the coexistence of an IR-UWB system based on an orthogonal sinusoidal correlation receiver (OSCR) with an IEEE 802.11a WLAN through a detailed simulation. The coexistence performance of the two systems is characterized in terms of the receiver's bit-error rates. Then, some approaches to interference mitigation are discussed.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.928-935
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• 2018

In this paper, a compact fully printable bandpass filter is suggested for a low-frequency channel 3.2 GHz ~ 3.7 GHz in the Ultra-Wideband (UWB) communication system. It is featured with a small geometry of $0.5{\lambda}_g/15$ and a low insertion loss despite using FR4 as a cheap substrate of a high dielectric loss. This is made possible by generating zeroth-order-resonance (ZOR) from one cell comprising two series resonances obviously separated from one shunt resonance as a third-order bandpass filter. Especially, the series resonance elements are combined with spur-lines bent by 90 degrees, which makes the port-impedance matched well and eliminates spurious hikes in the stopband, while the overall size remains almost unchanged. The design is carried out by setting up the equivalent circuit and the circuit simulation is checked by the full-wave EM analysis. The structure is manufactured and measured to show that the circuit modeling and EM simulation results agree with the measured data.

• Journal of Digital Contents Society
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• v.5 no.3
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• pp.171-175
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• 2004

In this paper, We applied CCI canceller to remove multi-user interference in co-channel environment and improved performance of TH PPM UWB-IR system. As a result, We could get reception performance that data transmission of high speed is available in small reception power applying CCI canceller. Also, We could get permission available channel capacity to maximum access number 40 in high speed transmission environment more than 100Mbps.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.1980-1985
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• 2010

This paper is about design of optimal structure of slot antenna array antenna with inner waveguide in accordance with the slot model, and fabrication of its prototype sample operating at the frequency of 24 GHz. Results of this work can be employed as a useful tool to develop and diversify slot antenna having superior performance and omni-directivity to that of current antenna. The implemented antenna demonstrates ultra-wideband performance for frequency ranges 24 GHz with the relatively high and flat antenna gain of 18.64dBi and low sidelobe levels. In addition, a $2{\times}8$ antenna array for phased-array systems and mm-wave sensor applications is also presented.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.1467-1470
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• 2002

한정된 주파수 문제를 해결하기 위해 제안된 초광대역 통신 시스템은 전 주파수 대역에 걸쳐 스펙트럼이 마치 기저 대역 잡음과 유사한 형태로 존재하여 타 통신 시스템에 간섭을 주지 않고 고속의 통신이 가능하며 반송파를 사용하지 않기 때문에 송 수신기의 소비 전력과 그 구조론 간략화 시킬 수 있다. 그러나 기존의 펄스 위치 방식(Pulse Positioning Modulation : PPM)은 주파수 스펙트럼 상에 불연속 전력 스펙트럼 성분이 존재하여 시스템의 효율을 저하된다. 본 논문에서는 불연속 전력 스펙트럼 성분이 발생하지 않고, 유클리드 거리가 최대가 될 수 있는 Antipodal 신호를 제안한다. 또한, 고주파 시뮬레이터인 Agilent 사의 Advanced Design System을 사용하여 Antipodal 신호를 이용한 변 복조기를 설계하여 구현 및 적용 가능성을 보였다.