• 대한전자공학회논문지TC
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• 제38권10호
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• pp.34-40
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• 2001

초광대역 통신은 전 주파수 대역에 걸쳐 스펙트럼이 존재하는 광대역 신호를 이용하는 방식이다. 이 신호의 스펙트럼은 마치 기저 대역 잡음과 유사한 형태로 존재하고 그 전력 또한 매우 낮게 구성할 수 있으므로, 타 통신 시스템에 간섭을 주지 않고 통신을 가능하게 한다. 따라서 본 논문에서는 평균값이 0이고 대칭성을 갖는 레일리 모노펄스 Antipodal 방식을 처음으로 적용하였다. 확률 과정에 의한 전력 스펙트럼을 분석한 결과, 기존의 펄스 위치 변조에서 발생되는 불연속 스펙트럼을 완전히 제거하여 스펙트럼의 억압도를 높이고, 오류 확률 및 전송 속도 면에서도 유리함을 보였다.

• Journal of electromagnetic engineering and science
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• 제17권1호
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• pp.44-49
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• 2017

A compact planar microstrip-fed ultra-wideband (UWB) antenna with a dual band-notched for UWB application is presented and analyzed. By inserting a U-shaped slot and inverted U-shaped slot into the pot-shaped radiator, two notched bands are achieved. By optimizing the width and length of the U-shaped slots and inverted U-shaped slot, a desired bandwidth of voltage standing wave ratio (VSWR) less than 2.0 can be achieved, ranging from UWB bands with notched dual bands. The proposed antenna is fabricated on an inexpensive FR-4 substrate with overall dimensions of $28.0mm{\times}39.5mm$. The measured results confirm that the proposed antenna covers from 1.775 to over 13.075 GHz with two rejection bands of around 3.325-3.925 GHz and 5.3125-6.025 GHz. In addition, the proposed antenna showed good radiation characteristics and gains in the UWB bands.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.27-30
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• 2004

This paper has been designed the TDMG(Time Delay Multiple Gaussian) pulse generator for UWB systems and analyzed the characteristics of UWB impulse. Composite two equal Gaussian pulses in a difference time lag, and then investigated TDMG pulse and modeled mathematically. Designed the TDMG pulse generator by ADS(Advanced Design System) to embody by using actual element with such mathematical model. As well as, this paper finally proved an excellence of the TDMG pulse generator by performing analysis through simulation.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.421-424
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• 2005

X-ray is currently most effective method in detecting small malignant breast tumors but has the several problems due to suppressing breast, ionizing radiation and not detecting small cancer. In this paper, a new method is proposed by using dielectric characteristics of pathological tissues and time delay of backscattered response. 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 is a key element of such detection system. Further study is ongoing to develop a commercial system.

• IEIE Transactions on Smart Processing and Computing
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• 제6권4호
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• pp.246-252
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• 2017

Non-invasive and non-restrictive methods for measuring the physiological functions of the human body are useful for health care, security, and surveillance. In this paper, a new method that extracts human heartbeat information by utilizing ultra-wideband (UWB) impulse radar is proposed. The amplitude spectra of received radar pulses reflected from the human body are accumulated at specific time intervals, and chirp z-transform (CZT) is used to extract the heartbeat frequency from the amplitude spectra. The heartbeat frequency can be extracted with high-frequency resolution in the frequency band of the heartbeat of interest using CZT. Experimental results to verify the performance of the proposed method show that a highly accurate extraction of the heartbeat frequency is possible using this method.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권2호
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• pp.202-207
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• 2015

A CMOS relaxation oscillator, with high robustness over process, voltage and temperature (PVT) variations, is designed in $0.18{\mu}m$ CMOS. The proposed oscillator, consisting of full-differential charge-discharge timing circuit and switched-capacitor based voltage-to-current conversion, could be expanded to a simple open-loop frequency synthesizer (FS) with output frequency digitally tuned. Experimental results show that the proposed oscillator conducts subcarrier generation for frequency-modulated ultra-wideband (FM-UWB) transmitters with triangular amplitude distortion less than 1%, and achieves frequency deviation less than 8% under PVT and phase noise of -112 dBc/Hz at 1 MHz offset frequency. Under oscillation frequency of 10.5 MHz, the presented design has the relative FS error less than 2% for subcarrier generation and the power dissipation of 0.6 mW from a 1.8 V supply.

• 대한임베디드공학회논문지
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• 제10권2호
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• pp.57-64
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• 2015

In this paper, we propose structures and power spectral densities of UWB radar transmitters of Short Range Automobile. While the conventional transmitters did not consider interferences from self and other automobiles, the proposed method of this paper can minimize interferences. First, we compare a structure of the proposed method with pulse train and pulse compression method. Then, by using mathematical analysis and computer simulations, we show that the proposed method is superior to others. Also we can set proper parameters in UWB radar's transmitter through the numerical method of mathematical results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.533-534
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• 2006

This paper presents the architecture design of a high-speed, low-complexity 128-point radix-$2^4$ FFT processor for ultra-wideband (UWB) systems. The proposed high-speed, low-complexity FFT architecture can provide a higher throughput rate and low hardware complexity by using 2-parallel data-path scheme and single-path delay-feedback (SDF) structure. This paper presents the key ideas applied to the design of high-speed, low-complexity FFT processor, especially that for achieving high throughput rate and reducing hardware complexity. The proposed FFT processor has been designed and implemented with the 0.18-m CMOS technology in a supply voltage of 1.8 V. The throughput rate of proposed FFT processor is up to 1 Gsample/s while it requires much smaller hardware complexity.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권4호
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• pp.415-424
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• 2016

This paper describes a high data rate proximity transmitter design for high resolution smartphone-mirrored display applications. A 2 Gb/s transmitter is designed with a low transmission power of -70 dBm/MHz and a wide bandwidth of nearly 3 GHz. A digital pre-correction method is employed in the transmitter to mitigate the inter-symbol interference problem. A carrier-based digital pulse shaping and a reconfigurable digital envelope generation methods are employed for robust operation by utilizing 20 phases from a 2 GHz phase-locked loop. A 6.5-9.5 GHz transmitter implemented in 65 nm CMOS achieves the maximum data rate of 2 Gb/s, consuming only 7.6 mW from a 1 V supply.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2007년도 하계종합학술대회 논문집
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• pp.93-94
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• 2007

이 논문은 시간도약 다중접속(time hopping multiple access: THMA) 초광대역(ultra wideband: UWB) 시스템에서 Modified Hermite Polynomial(MHP)을 기저펄스로 사용하는 M진 고속전송 기법을 제안하고, 시스템의 성능을 분석한다. MHP 펄스 차수들의 상호간 직교성을 이용하여 서로 다른 차수의 MHP 기저펄스 N개를 선형결합하여 M진으로 전송한다. MHP 기저펄스의 상호상관 함수를 구하여 제안하는 M진 시스템의 이론적인 성능을 분석하고, 모의실험을 통해서 기존의 M진 전송에 비해서 시스템의 비트오류확률(bit error rate: BER)이 개선됨을 보인다.