• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.9
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• pp.985-991
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• 2008

This paper presents a novel balanced mixer receiver front-end design based on a metamaterial structure applicable to differential-/common-mode excitation. This metamaterial structure functions as a leaky-wave antenna and provides in-trinsic common-mode suppression. Low LO leakage and high RF to LO isolation are achieved without additional filters for LO and RF paths. The metamaterial is based on a unit-cell which under a differential-mode excitation behaves like a composite right/left-handed(CRLH) metamaterial. In contrast, the metamaterial unit-cell is below cut-off under a common-mode excitation. Experimental results are used to verify the proposed metamaterial's differential-/common-mode characteristics. The metamaterial is integrated with a balanced mixer design resulting in an operation frequency range of $1.96{\sim}2.40$ GHz with an optimum mixer conversion loss of 21.1 dB at 2,4 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1313-1321
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• 2008

outphasing class-E power amplifier using composite right/left-handed transmission lines(CRLH-TL) is proposed at 2.4 GHz. The power combiner including CRLH-TL is designed to suppress the second and third harmonics to increase linearity and the output problem of the conventional outphasing amplifier is also solved by the proposed outphasing amplifier. So the P AE is improved. The measured maximum output power at the fundamental frequency shows 31.8 dBm, whereas the PAE shows 50 % with 14 dBm input power excited. The IMD3 is improved by 5 dB compared to that of conventional outphasing amplifier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.1
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• pp.47-53
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• 2015

In this paper, a novel fluid controlled phase tunable line using inkjet printed microfluidic composite right/left-handed(CRLH) transmission line(TL) is proposed. A CRLH-TL prototype has been inkjet-printed on a paper substrate using silver nano particle ink. In addition, a laser-etched microfluidic channel in poly methyl methacrylate(PMMA) has been integrated with the CRLH TL using inkjet-printed SU-8 as a bonding material. The proposed TL provides excellent phase-tuning capability that is dependent on the different fluidic materials used. As the fluid is changed, the proposed TL can have negative-phase, zero-phase, and positive-phase characteristics at 900 MHz and reflection coefficient is maintained to below -10 dB. The performance of the proposed TL is successfully validated using simulation and measurement results.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.35-41
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• 2009

대부분의 사람들은 의식하지 못하지만 세상은 오른손잡이 중심으로 이뤄져 있기 때문에 왼손잡이가 일상적으로 겪는 불편은 상상외로 많다. 우리가 일상에서 많이 사용하는 연장, 주방기구, 사무용품, 가전제품, 가구, 의류, 악기, 의료기기, 스포츠용품, 공공시설 등 이들 대부분이 오른손잡이에게 맞춰져 있어 왼손잡이들은 자신들의 왼팔을 비틀어서 사용하거나 주손이 아닌 오른손으로 부자연스런 자세로 사용할 수밖에 없다. 이에 따라 왼손잡이는 일상생활에 있어서의 상당한 불편을 느낄 뿐만 아니라 작업 능률의 저하, 재해나 상해를 입을 가능성이 높아질 수 있다. 본 연구는 무작위로 선정된 피설문자에 대한 설문 조사를 통하여 손잡이(handedness)와 관련된 통계수치를 제공하고 왼손잡이인 경우 왼손잡이로서 일상생활에서의 불편함, 작업능률의 저하여부, 오른손잡이 전용제품을 사용하여 상해를 입은 경험 등에 대해 조사하였다. 또한 왼손잡이도 편리하게 사용할 수 있으면 하는 제품이나 공공시설 등에 대한 이들의 주관적인 견해에 대해서도 조사하였다. 이를 토대로 왼손잡이를 위한 공구, 주방용품, 문구용품, 스포츠용품, 사무용품 등에 대하여 현재 적용되어 있는 상품에 대한 고찰과 향후 적용 가능 상품 및 공공시설에 대해 제안하였다.

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.196-201
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• 2013

In this paper, a dual-mode balanced filter with symmetric coupled composite right/left-handed transmission line is introduced. Unlike the other symmetric structure, this configuration has the ability to operate under both common- and differential-mode excitation. These properties are achievable through providing physical short circuit by means of ground vias at the center of each unit-cell along the symmetry plane of the structure. Because the CRLH unit-cells are operated under both common- and differential-mode excitation, we implemented a balanced filter using these properties. To validity these features, a five-cell four port coupled CRLH-TL is simulated, fabricated and measured and the obtained performances agree with the simulation results under both common- and differential-mode excitation.

• Korean Journal of Applied Biomechanics
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• v.25 no.4
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• pp.423-429
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• 2015

Objective : The purpose of this study was to investigate the effects of a body alignment correction program on asymmetrically developed squash players. Method : 30 experienced squash players who showed asymmetric body development, after evaluation of moire topography contour line shape, were involved in the experiment. All of them were right-handed and had more than five years of experience playing squash. Variables of body composition, moire topography and EMG were statistically compared between pre- and post- application of the 12-week body alignment correction program. The program consisted of 10-minute, left-handed forehand and backhand drive movements and 36 minutes performing 12 different yoga postures. Results : First, the body alignment correction program showed significant effects on the total weight, body fat percentage, and body mass index of the participants. Second, a decrease of right side inclined angles and an increase of left side inclined angles might result in a higher left-right symmetry rate and a better left-right balance; however the data was not statistically significant. Third, the EMG left-right deviation of erector spinae and latissimus decreased and the erector spinae muscle was thought to be more essential for vertebral movement and left-right asymmetry correction. Conclusion : A body alignment correction program, including yoga and opposite side exercises, could reduce left-right asymmetry.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.259-264
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• 2011

Does preferred hand show better performance than non-preferred hand in smart phone text entry using one hand. Is the performance of subjects who use left-preferred hand in smart phone text entry worse than that of others who use right preferred hand among the right handed. This study tried to address these two questions. Thirty young male undergraduate students typed a text using a smart phone which has a touch-based QWERTY keyboard two times with both hands, right and left hand, respectively. The completion time, errors were measured in the text entry tasks. All of participants were right handed, but half of them preferred right hand if they have to use one hand in smart phone text entry and other half preferred left hand. The percentage that preferred hand has better performance than non-preferred hand in smart phone text entry using one hand is less than 90% for right-preferred hand and less than 70% for left-preferred hand. The performance of left hand preferred students is not worse than that of the right hand preferred in one hand text entry of smart phone.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.12
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• pp.16-21
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• 2007

In this paper, the dual-band voltage-controled oscillator (VCO) using the composite right/left-handed (CRLH) transmission line (TL) and the tunable negative resistance based on the fin diode is presented. It is demonstrated that the CRLH TL can lead to metamaterial transmission line with the dual-band tuning capability. The dual-band operation of the CRLH TL is achieved by the frequency offset and the phase slope of the CRLH TL, and the frequency ratio of the two operating frequencies can be a non-integer. Each frequency band of VCO has to operate independently, so we have used the tunable negative resistance based on the pin diode. When the forward bias has been into the pin diode, the phase noise of VCO is $-108.34\sim-106.67$ dBc/Hz @ 100 kHz in the tuning range, $2.423\sim2.597$ GHz, whereas when the reverse bias has been fed into the pin diode, that of VCO is $-114.16\sim-113.33$ dBc/Hz @ 100 kHz in the tuning range, $5.137\sim5.354$ GHz.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.53-59
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• 2008

In this paper, a novel dual-band high-efficiency class-F power amplifier using the composite right/left-handed (CRLH) transmission lines (TLs) has been realized with one RF Si lateral diffusion metal-oxide-semiconductor field effect transistor (LDMOSFET). The CRLH TL can lead to metamaterial transmission line with the dual-band tuning capability. The dual-band operation of the CRLH TL is achieved by the frequency offset and the nonlinear phase slope of the CRLH TL for the matching network of the power amplifier. Because the control of the all harmonic components is very difficult in dual-band, we have managed only the second- and third-harmonics to obtain the high efficiency with the CRLH TL in dual-band. Also, the proposed power amplifier has been realized by using the harmonic control circuit for not only the output matching network, but also the input matching network for better efficiency. Two operating frequencies are chosen at 880 MHz and 1920 MHz in this work. The measured results show that the output power of 39.83 dBm and 35.17 dBm was obtained at 880 MHz and 1920 MHz, respectively. At this point, we have obtained the power-added efficiency (PAE) of 79.536 % and 44.04 % at two operation frequencies, respectively.

• Proceedings of the KOSOMBE Conference
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• v.1991 no.05
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• pp.71-73
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• 1991

In this study electrical impedance plethysmograph was developed and each ten digital blood flow was measured for eight normal males and a patint with digital arterial reconstruction surgery. Blood flow of the digit with surgery was approximately fourty percent compared to that of the other normal digit. For the normal subjects, right-handed subjects generally have larger blood flow in right fingers than that in left fingers while it was reverse for the left-handed subjects. The relative average magnitude of the digital blood flow is the third, first, second, fourth, and fifth digit in descending order for the left and right hand, respectively. Blood flow of the fifth digit for all subjects except one was the smallest among the five digits.