• Journal of IKEEE
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• v.22 no.3
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• pp.793-799
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• 2018

An improved design of Ultra Wide Band(UWB) Bow-Tie antenna, which can control an enhanced wide stop-band, is presented. The mutually coupled slot-pair improves and controls the rejection band. The UWB antenna is composed of an electromagnetically coupled Bow-Tie patch and a parasitic ground patch, whose working frequency is extended to full UWB range in this work. By adding slot-pairs on the main patch and optimizing, they can give any requested wide rejection bands and sharp skirt characteristics, as is often required for UWB antennas and multi-band antennas. All the parameters are precisely calculated by an adequate optimization method. The Particle Swarm Optimization(PSO) technique is appropriately adopted. The proposed design and method is proved to give and control the sharp-skirt wide stop-band to UWB Bow-Tie antennas.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.2
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• pp.117-122
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• 2009

In this paper, the performance of double binary turbo code is analyzed and simulated in ultra wide-band (UWB) systems employing multiple-antenna scheme. We consider both pulse position modulation-time hopping (PPM-TH) and pulse amplitude modulation-direct sequence (PAM-DS) UWB systems. The space time block code (STBC) scheme is adopted as a transmit diversity method. Also, receive diversity scheme is applied. And double binary turbo code is applied to the UWB system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6C
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• pp.376-383
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• 2011

Since the first arrival path may not be the strongest path of UWB(Ultra Wide Band) multipath channels, this makes ToA(Time-of-Arrival) estimation becomes a challengeable issue. Furthermore, because of ultra bandwidth of received signals, the compressed sensing theory is employed to reduce the complexity caused by very high Nyquist sampling rate in coherent UWB receivers. In this paper, we propose a ToA estimation scheme which provides precise estimation performance, while exploiting the benefits of compressed sensing-based UWB receivers. Simulation results show that the proposed scheme can outperform other low complexity schemes in a wide range of signal-to-noise ratios.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12A
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• pp.951-957
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• 2003

The analysis of RF performance requirement conditions on communication system is critical indicator to predict the performance of system. UWB(Ultra Wide Band) system which the standard is not established yet is difficult to derive the precise system performance requirement condition. Also, there are differences between conventional UWB system and multi-band system about RF performance requirement condition. In this thesis, the differences are analyzed and performance requirement conditions of multi-band UWB system are described on the basis of the differences. Throughput, maximum transmit power, and sensitivity of multi-band UWB system is varied with respect to the number of Sub-Bands. In addition, because of Multi-path effect, if PRF(Pulse Repetition Frequency) is changed, the Multi-path link margin is happened to compensate for Multi-path Energy Loss which is contributed by increasing of the Link Margin. According to Multi-path Margin, the variation of the resistance with respect to sensitivity and interference signal is observed and analyzed through the simulation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.12
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• pp.1661-1666
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• 2014

In this paper, a compact planar ultra wideband (UWB, 3.1~10.6GHz) multiple-input multiple-output (MIMO) antenna is proposed. This antenna consists of two monopole planar UWB antennas and T-shaped stub decoupling between two antennas. The T-shaped stub improve the isolation characteristic at the wide band. The evolution strategy(ES) algorithm is employed to optimized design. As a result, optimized antenna has a return loss less than -10dB and the isolation less than -15dB from 3.1GHz to 10.6GHz. During the optimization process, the antenna gain is enhanced at lower band and the envelope correlation coefficient(ECC) is lower than 0.003.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.81-89
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• 2009

We propose a D-ATR UWB (Differential-Average Transmitted Reference Ultra Wide Band) system based on impulse radio. The TR-UWB systems including traditional TR (Transmitted Reference) and ATR (Average TR), exhibit a problem of reduced data rate, since reference signals are additionally transmitted. To tackle this issue, the transmitter of the proposed D-ATR system employs a differential coding like the conventional D-TR system. In addition, the receiver of the proposed system has the structure that can improve signal-to-noise ratio of the reference template used in the correlation process, by recursively averaging the received reference signals like the conventional ATR system. The simulation results in the IEEE 802.15.4a UWB multipath channel models reveal that the proposed D-ATR system achieves much better bit error rate performance as compared to the conventional D- TR system.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.519-523
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• 2003

In this paper, we proposed a new ultra wide-band(UWB) antenna for UWB communication applications. The proposed antenna is composed of a rectangular plate having two steps, single slot on plate and partial ground plane. This antennas operated from 3.2 to 13 GHz. Details of the proposed antenna design and measured results are presented discussed.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.290-302
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• 2003

Ultra wide band (UWB) radio has recently attracted increased attention due to its expected unlicensed operation, and potential to provide very high data rates at relatively short ranges. In this article we briefly describe some main candidate multiple access and modulation schemes for UWB communications, followed with their power spectral density calculation and properties. We also present some illustrative capacity results, and provide a discussion of the impact of network topology on multiple access capacity.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.529-532
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• 2003

본 논문은 UWB(Ultra Wide-band) 통신 시스템에서 효과적인 신호 검출 알고리즘을 제안한다. UWB 통신 시스템은 차세대 통신 시스템으로 각광 받고 있는 기술로써, 매우 낮은 파워의 송신 신호를 사용한다. 그로 인해 잡음 및 다중 경로 환경하에서 신호 검출 알고리즘이 시스템 성능에 매우 중요한 부분으로 작용한다. 제안된 알고리즘은 신호 검출 성능을 높이기 위해, 신호의 정확한 위치를 잡는 Tracking과정에서 사용되는 DLL 구조를 활용하여 보다 세밀한 신호 탐색이 가능하다. 실험 결과 신호 위치를 기준으로 신호길이의 1/3 내에서 신호를 검출할 확률이 AWGN 15dB 이하에서 30% 정도 높아짐을 확인하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.34-39
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• 2007

UWB(Ultra Wide Band) system for high speed and high accurate location has been studying actively. This paper presents the design and implementation of RF transceiver for DS-CDMA(Direct Sequence-Code Division Multiple Access) UWB device. Major components of RF transceiver such as Low Noise Amplifier(LNA) and Band Pass Filter(BPF) are designed and then fabricated to meet wideband characteristics. The RF transceiver was implemented by the use of the fabricated components and commercial devices after carrying out performance simulation. Through the performance evaluation of the UWB RF transceiver with W-CDMA signal, the approach of design, implementation and evaluation of RF transceiver which is available to DS-CDMA UWB system is verified.