• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.439-444
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• 2020

In this paper, the analysis of the FSCS (frequency-selected coupling structure) as the coupling coefficient and multi-stage FSCS for enhanced bandstop bandwidth is suggested. The FSCS is composed by the connected coupled-line and open-stub. Basically, the resonance frequency of the FSCS is given by the electrical length of the stub, and the bandwidth is controlled by the coupling coefficient. Multi-stage FSCS is made by addition of another FSCS with the half electrical length. Manufactured bandstop filter using 3 stage FSCS is measured with the stopband of 177.3% and the maximum return loss of 1dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5C
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• pp.556-561
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• 2006

In this study, an ultra-wideband(UWB) signal model is considered to estimate the angle-of-arrivals(AOAs) of clusters in an UWB indoor-to-outdoor communication environment having random angle spreads. A conventional AOA algorithm for UWB estimates the directions of both clusters and multipath signals together and so has complex estimation procedure. In order to solve that problem, we propose a new clustered AOA estimation algorithm. The estimation technique based a well-known MUSIC algorithm is proposed and the estimates of the AOA on received clusters are obtained using the proposed technique. The proposed model and estimation technique are verified through computer simulations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.194-198
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• 2005

A novel ultra wideband microstrip-fed circular patch antenna having band stop characteristic in UNII band is presented. The band stop characteristic is realized by inverted-U shaped slot. The range of stop bandwidth can be adjusted by changing the length of the slot. The measured impedance bandwidth of the proposed antenna is from 2.9 GHz to 12.1 GHz with the stop band from 4.9 GHz to 6 GHz for VSWR<2. This antenna shows a monopole-like radiation pattern and flat gain characteristic throughout the operating frequency band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.3
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• pp.336-342
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• 2008

This paper suggests a CPW-fed UWB antenna with new hexagonal slot. To increase the impedance bandwidth of an antenna, the proposed antenna is designed with the hexagonal patch. Polygonal slot is inserted in the hexagonal patch to avoid interference with IEEE 802.11a. The proposed antenna was fabricated on FR-4 substrate with a relative dielectric constant 4.7 and thickness of 1.6 mm and measured for VSWR Characteristic and group delay. The fabricated antenna shows that the gain flatness is 4 dBi except at the band for IEEE 802.11a.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.1
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• pp.53-65
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• 2012

Recently wireless intra-vehicle communication has received a great interest from the automotive industry and ultra wideband (UWB) technology is considered as one of the potential candidate for this system. Many research works have been done on the measurement and modeling of intra-vehicle communication channel. However, very little work has been reported for the performance analysis of various PHY layer methods under the intra-vehicle communication environment. This paper is to study IEEE 802.15.4a standard in intra-vehicle channel and to evaluate its performance. Channel model in chassis and engine compartment is considered for evaluation. Through simulation BER performance of system with different receiver structures is analyzed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.59-64
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• 2011

Ultra wideband radars attract considerable attention as a short range automotive radar because of its high range resolution. Radar signal reflected from a target often contains unwanted echoes called as clutter, so the detection of target is difficult due to clutter echoes. Therefore, it is important to investigate the radar detector for better detecting from the reflected signals. In this paper, the optimal detector is obtained for various mean and variance value in log-normal clutter environment. The types of non-coherent detectors used are square law detector, linear detector, and logarithmic detector. The performances of detectors are compared in log normal clutter environment and the suitable detector is determined for automotive short range radar application.

• ETRI Journal
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• v.34 no.5
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• pp.674-683
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• 2012

We propose a slot antenna consisting of a rectangular slot on the ground plane, fed by a microstrip line with a rectangular-ring-shaped tuning stub that can be deployed in ultra-wideband (UWB) communication systems to avoid interference with wireless local area network (WLAN) communication. Our antenna can achieve a single band-notched property from the 5 GHz frequency to the 6 GHz frequency owing to a controllable band notch that uses L- and J-shaped parasitic elements. The antenna characteristics can be modified to tune the band-notched property (4 GHz to 5 GHz or 6 GHz to 7 GHz) and the bandwidth of the band notch (1 GHz to 2 GHz). Furthermore, the shifted notch with enhanced width of the band notch from 1 GHz to 1.5 GHz is described in this paper. The UWB slot antenna and L- and J-shaped parasitic elements also provide the band-rejection function for reference in the WiMAX (3.5 GHz) and WLAN (5 GHz to 6 GHz) regions of the spectrum. Experiment results evidence the return loss performance, radiation patterns, and antenna gains at different operational frequencies.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.36-43
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• 2012

Ultra-wideband propagation measurement results for body area network scenarios are presented. We assumed several different scenarios for around-body and on-body propagations, and for each scenario, we conducted both time domain and frequency domain measurements in an anechoic chamber. For the around-body case, we investigated the effects of human body parts blocking line-of-sight, which could be accounted for by diffraction. On-body measurement results indicate a more complicated propagation mechanism exists in on-body propagation than in around-body propagation and antenna characteristics are affected.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.10
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• pp.802-809
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• 2017

This paper presents a novel apnea detection and respiration rate estimation method using impulse-radio ultra-wideband (IR-UWB) radar. The proposed method utilizes amplitude, time of arrival, and power in the selected band. The experimental results show that respiration rate can be estimated accurately using proposed method. And, it is shown that the selectivity between apnea and respiration can be improved more than 50 dB using the proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.303-307
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• 2008

In this paper, a new co-planar waveguide ultra-wideband aperture is designed. The designed antenna consists of a rectangular aperture on a determined ground plane and a mushroom shaped stub. The mushroom-shaped stub, which is simple, convenient to analyze and optimise, has less parameter. This antenna has compact aperture size $21.1{\times}8.1mm^2$, designed on FR-4 substrate with dielectric constant of 4.3, thickness of l.5mm. CPW fed planar antenna has the advantages of wide-bandwidth, low-cost and easy interaction with the radio frequency front end circuitry.