• 전기전자학회논문지
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• 제17권2호
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• pp.176-181
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• 2013

This paper presents a CMOS impulse radio ultra-wideband (IR-UWB) receiver implemented using IBM 0.13um CMOS technology for inner/inter-chip wireless interconnection. The IR-UWB receiver is based on the non-coherent architecture which removes the complexity of RF architecture (such as DLL or PLL) and reduces power consumption. The receiver consists of three blocks: a low noise amplifier (LNA) with active balun, a correlator, and a comparator. Simulation results show the die area of the IR-UWB receiver of 0.2mm2, a power gain (S21) of 12.5dB, a noise figure (NF) of 3.05dB, an input return loss (S11) of less than -16.5dB, a conversion gain of 18dB, a NFDSB of 22. The receiver exhibits a third order intercept point (IIP3) of -1.3dBm and consumes 22.9mW of power on the 1.4V power supply.

• Journal of electromagnetic engineering and science
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• 제17권2호
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• pp.65-70
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• 2017

The design and implementation aspects of a new single-balanced mixer for ultra-wideband (UWB) applications are presented in this study. The proposed mixer utilizes a miniaturized UWB ring coupler as a balun, consisting of a pair of in-phase and inverted-phase transitional structures. The well-balanced UWB performance of the ring coupler, aside from the optimized diode matching, results in improved conversion loss and inter-port isolations for a wide bandwidth. The size of the implemented single-balanced diode mixer is reduced to about 60% of the area of the conventional single-balanced ring diode mixer. The measured results of the proposed mixer exhibit an average conversion loss of 7.5 dB (minimum 6.7 dB) and a port-to-port isolation of greater than 18 dB over a UWB frequency range of 3.1-10.6 GHz. The measured results agree well with the simulated results.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.400-405
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• 2018

This paper presents a compact ultra-wideband (UWB) flexible monopole antenna design on a paper substrate. The proposed antenna is made of iterations of a circular slot inside an octagonal metallic patch. This fractal-based geometry has been deployed to achieve compactness along with improved bandwidth, measured reflection coefficient -10 dB bandwidth ranging from 2.7 to 15.8 GHz. The overall size of the antenna is $26mm{\times}19mm{\times}0.5mm$, which makes it a compact one. The substrate used is paper and the main features like environment friendly, flexibility, green electronics applications and low cost of fabrication are the key factors for the proposed antenna. The aforementioned UWB prototype is suitable for many wireless communication systems such as WiMAX, WiFi, RFID and WSN applications. Antenna has been tested for the effect of bending by placing it over a curved surface of a very small radius of 10 mm.

• Journal of Communications and Networks
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• 제14권5호
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• pp.501-509
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• 2012

This paper proposes a joint timing synchronization, channel estimation, and data detection for the impulse radio ultra-wideband systems. The proposed timing synchronizer consists of coarse and fine timing estimation. The synchronizer discovers synchronization points in two stages and performs adaptive threshold based on the maximum pulse averaging and maximum (MAX-PA) method for more precise synchronization. Then, iterative channel estimation is performed based on the discovered synchronization points, and data are detected using the selective rake (S-RAKE) detector employing maximal ratio combining. The proposed synchronizer produces two signals-the start signal for channel estimation and the start signal for start frame delimiter (SFD) detection that detects the packet synchronization signal. With the proposed synchronization, channel estimation, and SFD detection, an S-RAKE receiver with binary pulse position modulation binary phase-shift keying modulation was constructed. In addition, an IEEE 802.15.4a channel model was used for performance comparison. The comparison results show that the constructed receiver yields high performance close to perfect synchronization.

• Journal of Communications and Networks
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• 제11권3호
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• pp.287-296
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• 2009

Although asymptotic bounds of wireless network capacity have been heavily pursued, the answers to the following questions are still critical for network planning, protocol and architecture design: Given a three-dimensional (3D) network space with the number of active users randomly located in the space and using the wireless communication technology, what are the expected per-flow throughput, network capacity, and network transport capacity? In addition, how can the protocol parameters be tuned to enhance network performance? In this paper, we focus on the ultra wideband (UWB) based wireless personal area networks (WPANs) and provide answers to these questions, considering the salient features of UWB communications, i.e., low transmission/interference power level, accurate ranging capability, etc. Specifically, we demonstrate how to explore the spatial multiplexing gain of UWB networks by allowing appropriate concurrent transmissions. Given 3D space and the number of active users, we derive the expected number of concurrent transmissions, network capacity and transport capacity of the UWB network. The results reveal the main factors affecting network (transport) capacity, and how to determine the best protocol parameters, e.g., exclusive region size, in order to maximize the capacity. Extensive simulation results are given to validate the analytical results.

• 한국통신학회논문지
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• 제34권3A호
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• pp.205-212
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• 2009

본 논문에서는 IEEE 802.15.4a를 기반으로 한 IR-UWB (Impulse Radio - Ultra-wideband) 시스템에서 잔여 주파수 오프셋의 영향을 줄이는 채널 추정 기법을 제안한다. 실제로 IR-UWB 수신기는 제한된 프리앰블 심볼의 개수 때문에 주파수 동기를 완벽하게 수행할 수 없다. 따라서 잔여 주파수 오프셋이 존재하고 이 영향으로 채널추정 과정에서 상당한 오류가 발생하게 된다. 제안된 채널 추정 기법은 채널 추정과정에서 얻어낸 다중경로 프로파일을 이용하여 주파수 동기에 대한 정보를 획득하고 그것을 이용함으로써 제한된 수의 프리앰블 심볼을 가지고도 잔여 주파수 오프셋을 보상하고 잔여 주파수 오프셋에 의한 채널 추정 오류를 수정하여 정확한 채널 상태 정보를 추정하는 기법이다. 제안된 알고리즘을 IEEE 802.15.4a에서 제시한 채널 모델에 적용하여 모의실험 하였으며 제안된 채널 추정 알고리즘과 기존의 채널 주정 알고리즘을 비교 분석하여 성능이 개선됨을 확인하였다.

• Journal of Information Processing Systems
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• 제13권4호
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• pp.677-688
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• 2017

In order to solve the undetected probability of multiple targets in ultra-wideband (UWB) through-the-wall radar imaging (TWRI), a time-delay and amplitude modified back projection (BP) algorithm is proposed. The refraction point is found by Fermat's principle in the presence of a wall, and the time-delay is correctly compensated. On this basis, transmission loss of the electromagnetic wave, the absorption loss of the refraction wave, and the diffusion loss of the spherical wave are analyzed in detail. Amplitude compensation is deduced and tested on a model with a single-layer wall. The simulating results by finite difference time domain (FDTD) show that it is effective in increasing the scattering intensity of the targets behind the wall. Compensation for the diffusion loss in the spherical wave also plays a main role. Additionally, the two-layer wall model is simulated. Then, the calculating time and the imaging quality are compared between a single-layer wall model and a two-layer wall model. The results illustrate the performance of the time-delay and amplitude-modified BP algorithm with multiple targets and multiple-layer walls of UWB TWRI.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.505-506
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• 2006

PD(partial discharge) occurred from variable PD sources in air may be the cause of breakdown in high voltage equipment which affect huge outage in power system. Identification and localization of PD sources is very important for engineer to cope with huge accident beforhand. PD phenomena can be detected by acoustic emission sensor or electromagnetic sensor like antenna. This paper has investigated the identification method using PCA(principal component analysis) for the PD signals from variable PD sources, for which the electric field distribution and PD inception voltages were simulated by using commercial FEM program. PD signals was detected by ultra wideband antenna. Their own features were extracted as the frequency coefficients transformed with FFT(fast fourier transform) and used to obtain independent pincipal components of each PD signals.

• 한국항행학회논문지
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• 제10권3호
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• pp.268-275
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• 2006

가정과 사무실 정보 응용 및 서비스의 급격한 확산은 광대역 근거리 멀티미디어 통신을 가능하게 하는 새로운 무선 기술을 필요로 하고 있다. 고품질 미디어와 고속의 무선 연결을 위한 요구에 의하여 IEEE 표준화 그룹은 WPAN을 위한 고속 물리 계층을 고려하고 있다. 협대역의 펄스 전송을 기반으로 하는 UWB 다중 접속 기술은 고속의 서비스 제공, 낮은 전력 소모, 정확한 측위를 제공할 수 있는 응용 중의 하나이다. 본 논문에서는 전력 제어된 UWB 디바이스로 구성된 무선 센서 네트워크에서 페이딩 환경에 대한 UWB의 BER 성능을 평가하기 위한 방법론을 제시한다. 얻어진 결과는 주어진 네트워크 구조에 따른 성능 분석을 위하여 사용될 수 있으며 UWB 홈 센서 네트워크를 위한 유용한 디자인 아이디어를 제공할 수 있다.

• 한국전자파학회논문지
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• 제30권3호
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• pp.236-242
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• 2019

UWB(Ultra-WideBand)는 수 GHz 이상 광대역의 매우 짧은 신호를 이용하여 고속의 송수신이 가능한 기술로서, 최근 레이다 분야에 응용되고 있다. IR(Impulse Radio)-UWB 레이다의 경우, 높은 분해능으로 모션 인식 분야에도 적용되고 있다. 따라서, 본 논문에서는 IR-UWB 레이다를 이용한 모션 인식에 관한 연구를 진행하였다. 모션에 대한 데이터를 획득하기 위해 개발 환경을 구축하고, 성능 향상을 위한 신호처리 알고리즘을 구현하였다. 그리고 신호처리 결과를 바탕으로 모션의 특징 추출과 학습을 통해 성능을 검증하였다.