• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.2
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• pp.53-57
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• 2008

This paper designed and fabricated the printed dual monopole antenna with CPW feeder for PCS and UWB(Ultra-Wide Band) band. In this paper, modified dual monopole antenna is proposed transform conventional monopole antenna to get dual band frequency. The dual monopole antennas have dual band, broad bandwidth and omni-directional radiation patterns, as it is the conventional monopole antenna. As one monopole operated a stub to match feed line with antenna, we are obtained easy an ideal impedance matching. It is increased band width of impedance. The antenna bandwidth is about 1350MHz (1.69~2.04[GHz]z]) at 1st resonance frequency, 2,670MHz (4.33~6[GHz]) at 2nd, resonance frequency, and, 3,980MHz (6.1~10.08[GHz]) at 3th resonance frequency on VSWR$$\leq_-$$2, and then we can be got not only 1.75~1.87 [GHz] PCS band but also, UWB band.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.305-314
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• 2007

In this paper, we suggested a CPW-fed UWB antenna with uni-planar sectoral structure. The area where radiation device face ground is designed to have the shape of tapered slot based on exponential function. We modified a rectangular bow-tie dipole structure antenna and thus formed a multi-resonant mode. From this, we expanded the impedance bandwidth and made a feature satisfying VSWR of less than 2 between $3.1\sim10.6GHz$. The test result showed that the return loss less than -10 dB was met in the full-band UWB system and maximum gain of $0.9\sim3.1dB$ was made with the half-power beamwidth of $40.1\sim89.9^{\circ}$ on XY plane(Theta, $Phi=90^{\circ}$) and the full band. By using CPW-fed structure with no ground on the back of the substrate, the suggested antenna is easy to design and its miniaturization is also possible.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.2
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• pp.387-392
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• 2022

In addition to complying with access standards for facilities that require infection control (operating rooms, delivery rooms, intensive care units, etc.) in accordance with the 2019 Medical Care Act Enforcement Regulations, entry, exit, contact information, etc. for entry and exit, the criteria for entering and exiting special rooms of medical institutions have been revised so that records of facts are kept for one year. However, even now, the inconvenience continues due to the fact that such contents are created by hand or due to errors. For this reason, this study designed and implemented a system that provides automatic opening, closing, and accessing record storage functions for authorized users using IoT devices and UWB technology, and we expected that the convenience of the visitors and systemized access control will be possible.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11B
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• pp.1501-1509
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• 2001

Recently, the use of wireless communication systems has been rapidly increasing, which results in a difficult problem in efficient control of limited frequency resources. As a way of solving this problem, the ultra wideband time hopping impulse radio system attracts much attention. The impulse radio system communicates pulse position modulated data using Gaussian monocycle pulses of very short duration less than 1 nsec. Thus the transmitted signal has very low power spectral density and ultra wide bandwidth from near D.C. to a few GHz. It is blown that it hardly interferes with the existing communication systems because of its very low power spectral density. The purpose of this paper is to characterize multipath propagation of the impulse radio signal and to evaluate the performance of the correlator-based receiver for the multipath environments. In this paper, we consider the deterministic two-path model and the statistical indoor multipath model of Saleh and Valenzuela. For the two-path model the output of the correlator with the ideal reference waveform varies according to the relative difference between the indirect path delay and the time interval of PPM, and to the indirect path gains. In addition, the characteristics of bit error rates is measured for the two models through computer simulation. The simulation results indicate that the performance of the impulse radio system depends both on the relative difference between the indirect path delay and the time interval of PPM, and on the indirect path gains. Furthermore, it is observed that the reference signal designed for the AWGN channel can not be applied to the multipath channels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.117-122
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• 2006

A CMOS LNA based on a single-stage cascode configuration is designed for MB-OFDM ultra-wide band(UWB) systems. Wideband($3.1GHz\~4.9GHz$) input matching is performed using a simple bandpass filter to minimize the chip size and the noise figure degradation. The simulation results using $0.18{\mu}m$ CMOS process parameters show a power gain of 9.7dB, a 3dB band width of $2.1GHz\~7.1GHz$, a minimum NF of 2dB, an IIP3 of -2dBm. better than -11.8dB of input matching while occupying only $0.74mm^2$ of chip area. It consumes 25.8mW from a 1.8V supply.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.12
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• pp.2461-2468
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• 2015

Sinuous antenna is utilized in a number of application like direction-finding system that require ultra wideband, but because of high input impedance of the antenna, it is difficult to design low-profile antenna and balun. In this study, we used Babinet's principle and proposed linear 2-arm slot sinuous antenna that is divided sinuous 6 cell with equal spacing between the most largest radius $R_1=31.83mm$ and the smallest radius $R_p=1.7mm$ instead of exponential 2-arm strip sinuous antenna for 2-18[GHz] frequency band to obtain low input impedance, and we have studied -10dB bandwidth of antenna when has been fed by $80{\Omega}$ instead of $188{\Omega}$ at feeder point. As a result, we have obtained return loss below than -10dB for about 4-18[GHz] frequency range in the case of slot antenna, but at all frequency band, return loss was above -10dB in the case of strip antenna.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.561-570
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• 2009

Ultra-wideband communication systems based on impulse radio have merits that are possible for the high data rate transmission, high resolution ranging are positioning system. Conventionally, in order to accomplish these features, the high-speed ADC (Analog to Digital Convertor) is necessary to apply radio determination system operating in time domain. However, considering low rate - wireless personal area network (LR-WPAN) aims to low-cost hardware implementation, the expensive ADC converting GHz sampling per second is not appropriate. So, this paper introduces a low complex AR (Auto Regressive) model based non-coherent ranging scheme operating in frequency domain with using low-speed ADC utilizing analog Voltage Control Oscillator (VCO) mode for the frequency domain transformation. To verify the superiority of the proposed ranging and location algorithm working in frequency domain, the suggested IEEE 802.15.4a TG channel model is used to exploit affirmative features of the proposed algorithm with conducting the simulation results.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.5 no.3 s.11
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• pp.13-23
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• 2006

The system using UWB is processing brisk study with Bluetooth among the wireless access that is major technology in Telematics. The low complexity and cost for realization is advantage of UWB have communication of high speed. Mamy papers have published on the timing jitter effect on system performance except for the UWB system. In this paper, we analyze the effect of timing jitter on M-ary UWB system using orthogonal Hermite pulse and perform the simulation to show symbol error rate performance. For theoretical analysis, we derive correlation function of orthogonal Hermits pulse with closed form, and as well upper bound of Symbol Error Probability for M-ary orthogonal Hermite pulse system mathematically. It is found that numerical analysis is accurate enough through simulation.

• 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.