• Title/Summary/Keyword: ultra wideband signal

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Performance Improvement of Radar Target Classification Using UWB Measured Signals (광대역 레이다 측정 신호를 이용한 표적 구분 성능 향상)

  • Lee, Seung-Jae;Lee, Sung-Jun;Choi, In-Sik;Park, Kang-Kuk;Kim, Hyo-Tae;Kim, Kyung-Tae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.10
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    • pp.981-989
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    • 2011
  • In this paper, we performed radar target classification for the five scale models using ultra-wideband measured signal. In order to compare the performance, the 2 GHz(2~4 GHz), 4 GHz(2~6 GHz), and 6 GHz(2~8 GHz) bandwidth were used. Short time Fourier transform(STFT) and continuous wavelet transform(CWT) are used for target feature extraction. Extracted feature vectors are used as input for the multi-layerd perceptron(MLP) neural network classifier. The results show that as the bandwidth is wider, the performance is better.

Development of a Wideband Power Sensor for the Measurement of Wireless Power (무선 주파수 전력 측정을 위한 광대역 전력 센서 개발)

  • Hwang, Mun-Su;Na, In-Ho;Gu, Ja-Gyeong;Lim, Jong-Sik;Ahn, Dal
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.12
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    • pp.3600-3607
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    • 2009
  • This paper describes the development of a power sensor for wireless signal over the ultra wideband range of 300~3800MHz with the detecting range of 150mW~150W. The proposed power sensor fundamentally has the function of not only detecting wireless power, but recognizing frequency and measuring VSWR. The development of the power sensor is completed through the design of dual directional coupler, design of power detector block which produces DC data using the corresponding RF input power level, and establishment of collecting the exact calibration data. The dual directional coupler has the operating frequency of 300~3800MHz with the 0.085dB of insertion loss, and directivity of 30dB at least at 3800MHz. The developed power sensor has the capability of power sensing with less than 0.25dB of resolution as well as measuring VSWR of 1.17~1.96 under the practical operating situation of very high power up to 150W at 300~3800MHz.

Interference Avoidance Technology in Cognitive Based MB-OFDM UWB System (인지 기반 MB-OFDM UWB 시스템에서의 간섭 회피 기술)

  • Sung, Tae-Kyung;Weon, Young-Su;Cho, Hyung-Rae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.6
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    • pp.677-687
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    • 2008
  • CR technology is an intelligent technology which can sense the spectrum environment an adaptively adjust the parameters for wireless transmission. In this paper, by using CR-UWB, the spectrum efficiency of the transmission channel is largely improved; Furthermore, the interference to other system can be effectively avoided. In this paper, we propose a solution on interference problem of UWB system using cognitive radio. We use interference temperature model of cognitive radio that has proposed by FCC for estimating interference signal. Calculating channel capacity of UWB system with interference temperature, we suggest how to solve interference problem. We have used genetic algorithm in cognitive engine's calculation precess. The proposed UWB System with cognitive radio shows very efficient in solving interference problem.

Performance Evaluation of Time Hopping Binary PPM Impulse Radio System for Indoor Multiple Access Communication (실내 다원접속 통신을 위한 TH Binary PPM IR 시스템의 성능 평가)

  • 이양선;강희조
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.6 no.7
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    • pp.1032-1037
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    • 2002
  • In this paper, derived monocycle pulse that application is possible within permission frequency band (3.1 ~ 10.6GHz) that establish in FCC. Also, PPM modulated TH IR system simulator is designed in AWGN environment. It is analyzed monocycle pulse specific property and system performance using simulator. Also, analyzed BER performances of IR system in multiple access interference environment using proposed parameters. According to result, application of possible pulse duration$(t_n)$ is very limited by 0.04~0.0326 ns in permission frequency range that establish in FCC. In the case of same pulse signal power, we could know that system performance changes by $N_s$ regardless of pulse duration. IR system that need high speed transmission more than 50 Mbps in multiple access interference environment could know that very serious performance decrease by multiple access Interference happens.

Antenna Selection Scheme Using Noncoherent Receivers for Off-Body High Data Rate WBAN (신체 외부 고속 통신에서 Noncoherent 수신기 기반의 안테나 선택 기법)

  • Park, Jong-Seok;Hwang, Jae-Ho;Jang, Sung-Jeen;Kim, Jae-Moung;Lee, Hyung-Soo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.8 no.6
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    • pp.88-97
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    • 2009
  • As the development of wireless techniques, transmission technology of body area network plays an important role in realizing a welfare society by combining IT and BT when applying to vehicles. Off-body WBAN (Wireless Body Area Network) systems for video data transmission require low battery consumption and high data rate. To satisfy the requirement, UWB has been considered as a promising candidate for high rate WBAN. This paper introduces an antenna selection technique for ultra-wideband based off-body WBAN system with low complexity. In this paper, we propose an antenna selection scheme using non-coherent receiver for off-body high data rate WBAN system. The proposed receiver antenna selection method takes advantage of the characteristic of BPPM (Binary Pulse Position Modulation). With the property of BPPM, this scheme calculates the approximate SNR of the received signal with non-coherent receiver.

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Feasibility Study for the Development of a Device for Pathological Tissue (병리학적 조직 진단장치 개발에 대한 타당성 분석 연구)

  • Ko Chea-Ok;Park Min-Young;Kim Jeong-Lan;Lee Ae-Kyoung;Choi Hyung-Do;Choi Jae-Ic;Pack Jeong-Ki
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.4 s.107
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    • pp.341-350
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    • 2006
  • In this paper, a new method for detecting breast cancer is proposed, which utilizes dielectric characteristics of pathological tissues and time delay of back scattered response, and its feasibility was investigated. We have developed a detection algorithm and verified it by numerical simulation and measurement for a prototype system. For a prototype system, we have fabricated experimental model(artificial breast with a cancer) and UWB(ultra-wideband) antenna. The results of the measurement simulation show an excellent detection capability of a cancer tissue. It is found that a good UWB antenna and a good calibration signal are key elements of such detection system. Further study is ongoing to develop a commercial system.

Space-Frequency Block Coded Single Side Band SC-FDMA Transmission System (주파수 공간 블록 부호화된 단일 측대 파형 SC FDMA 전송 시스템)

  • Won, Hui-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.7
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    • pp.423-429
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    • 2019
  • Recently, a variety of methods for the performance improvement of ultra-high speed wideband wireless transmission systems have been suggested. This paper proposes a space-frequency (SF) block coded single side band (SSB) single carrier (SC)-frequency division multiple access (FDMA) transmission system. In the proposed SSB SC-FDMA system, SF block code is implemented with the complex conjugates, which are formed from discrete Fourier transform (DFT) spreading of pulse amplitude modulation (PAM) signals. As a result, transmit diversity gain can be obtained in the proposed SF block coded SSB SC-FDMA system without any significant increase of the system computational complexity. The simulation result shows that the signal-to-noise power ratio (SNR) performance of the proposed SF block coded SSB SC-FDMA system is approximately 4 dB better than the SNR performance of the conventional SSB SC-FDMA system with single transmit antenna at a symbol error rate (SER) of $10^{-2}$.

Location Error Reduction method using Iterative Calculation in UWB system (Iterative Calculation을 이용한 UWB 위치측정에서의 오차감소 기법)

  • Jang, Sung-Jeen;Hwang, Jae-Ho;Choi, Nack-Hyun;Kim, Jae-Moung
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.45 no.12
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    • pp.105-113
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    • 2008
  • In Ubiquitous Society, accurate Location Calculation of user's device is required to achieve the need of users. As the location calculation is processed by ranging between transceivers, if some obstacles exist between transceivers, NLoS(Non-line-of-Sight) components of received signal increase along with the reduction of LoS(Line-of-Sight) components. Therefore the location calculation error will increase due to the NLoS effect. The conventional location calculation algorithm has the original ranging error because there is no transformation of ranging information which degrades the ranging accuracy. The Iterative Calculation method which minimizes the location calculation error relys on accurately identifying NLoS or LoS condition of the tested channel. We employ Kurtosis, Mean Excess Delay and RMS Delay spread of the received signal to identify whether the tested channel is LoS or NLoS firstly. Thereafter, to minimize location calculation error, the proposed Iterative Calculation method iteratively select random range and finds the averaged target location which has high probability. The simulation results confirm the enhancement of the proposed method.

A 30 GHz Band Low Noise for Satellite Communications Payload using MMIC Circuits (MMIC 회로를 이용한 위성중계기용 30GHz대 저잡음증폭기 모듈 개발)

  • 염인복;김정환
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.11 no.5
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    • pp.796-805
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    • 2000
  • A 30GHz band low noise amplifier module, which has linear gain of 30dB and noise figure of 2.6dB, for 30GHz satellite communication transponder was developed by use of MMIC and thin film MIC technologies. Two kinds of MMIC circuits were used for the low noise amplifier module, the first one is ultra low noise MMIC circuit and the other is wideband and high gain MMIC circuit. The pHEMT technology with 0.15$mu extrm{m}$ of gate length was applied for MMIC fabrication. Thin film microstrip lines on alumina substrate were used to interconnect two MMIC chips, and the thick film bias circuit board were developed to provide the stabilized DC bias. The input interface of the low noise amplifier module was designed with waveguide type to receive the signal from antenna directly, and the output port was adopted with K-type coaxial connector for interface with the frequency converter module behind the low noise amplifier module. Space qualified manufacturing processes were applied to manufacture and assemble the low noise amplifier module, and space qualification level of environment tests including thermal and vibration test were performed for it. The developed low noise amplifier was measured to show 30dB of minimum gain, $\pm$0.3dB of gain flatness, and 2.6dB of maximum noise figure over the desired operating frequency range from 30 to 31 GHz.

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