• Journal of Institute of Control, Robotics and Systems
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• v.14 no.10
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• pp.991-997
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• 2008

A new RMRAC scheme far the PMSM current regulation is proposed in a synchronous frame, which is completely free from the parameter's uncertainty. A current regulator of PMSM is the inner most loop of electromechanical driving systems and plays a foundation role in the control hierarchy. When the PMSM runs in high speed, the cross-coupling terms must be compensated precisely for large system BW. In the proposed RMRAC, the input signal is composed of a calculated voltage defined by MRAC law and an output of the disturbance compensator. The gains of feed forward and feedback controller are estimated by the proposed modified gradient method, where the system disturbances are assumed as filtered current regulation errors. After the compensation of the system disturbance from error information, the corresponding voltage is fed forward to control input to compensate for real disturbances. The proposed method robustly compensates the system disturbance and cross-coupling terms. It also shows a good realtime performance due to the simplicity of control structure. Through real experiments, the efficiency of the proposed method is verified.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.174-179
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• 2013

This paper presents a capacitor loaded tunable bandpass chip filter using multiple split ring resonators (MSRRs) with two transmission zeros. To obtain high selectivity and minimize the chip size, asymmetric feed lines are adopted to make a pair of transmission zeros located on each side of passband. Compared with conventional filters using cross-coupling or source-load coupling techniques, the proposed filter uses only two resonators to achieve high selectivity through a pair of transmission zeros. In order to optimize selectivity and sensitivity (insertion loss) of the filter, the effect of the position of asymmetric feed line on transmission zeros and insertion loss is analyzed. The SOI-CMOS switched capacitor composed of metal-insulator-metal (MIM) capacitor and stacked-FETs is loaded at outer rings of MSRRs to tune passband frequency and handle high power signal up to +30 dBm. By turning on or off the gate of the transistors, the passband frequency can be shifted from 4GH to 5GHz. The proposed on-chip filter is implemented in 0.18-${\mu}m$ SOI CMOS technology that makes it possible to integrate high-Q passive devices and stacked-FETs. The designed filter shows miniaturized size of only $4mm{\times}2mm$ (i.e., $0.177{\lambda}g{\times}0.088{\lambda}g$), where ${\lambda}g$ denotes the guided wave length of the $50{\Omega}$ microstrip line at center frequency. The measured insertion loss (S21)is about 5.1dB and 6.9dB at 5.4GHz and 4.5GHz, respectively. The designed filter shows out-of-band rejection greater than 20dB at 500MHz offset from center frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.7
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• pp.663-668
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• 2003

In this paper, a CPW fed slot antenna with novel broadband feed structure is presented. To enhance the impedance bandwidth of the slot antenna we proposed the broadband feed structure of new bow-tie slot which is combined with four λ/2 rectangular radiation slot and inductively coupled. The measured 10 dB impedance bandwidth is about 60 %(5.2∼9.4 GHz) and the simulated antenna gain is about 6 dBi at 7.36 GHz.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.1038-1042
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• 2003

In order to evaluate dynamic impedance of a hand-arm system it is necessary to measure the hand-transmitted vibration and the reaction force at the same time while gripping the vibrating handle. In the study a device was developed to measure both the vibration and the force. The device consists of a measurement handle with four strain gauge and two accelerometers and a PC based control system with a program for the signal processing and evaluation of the hand-transmitted vibration and reaction force. The handle was installed on the vibration shaker so that it can move by the generated signal from the control system. As an application of the system dynamic reaction force and the frequency weighted acceleration at the handle attached to the shaker were measured at various grip force and feed force. This system will be very useful in the area of impedance measurement and the evaluation of performance of anti-vibration gloves.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.1
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• pp.9-15
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• 2011

In this paper, we designed and fabricated a dual-band bandpass filter which can control upper and lower bandwidth using the transformed E-shaped dual-mode resonator. The filter is made the coupling between even-mode not to affect odd-mode resonant frequency by the transformed resonator to control upper bandwidth effectively. The cross coupling between input and output feed lines was employed to improve stopband characteristic. The bandpass filter has been designed to indicate the same bandwidth at center frequency 2 GHz and 3 GHz to show to control bandwidth.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.32-37
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• 2007

This paper proposes a dual-mode ultra precision positioning system for machine tools and measuring machines. The objective was to position a machine table with a picometer order of resolution, i.e., pico-positioning. A twist-roller friction drive (TFD) was used in coarse-mode positioning. The TFD, which was driven by an AC servomotor, is a kind of lead screw in mechanical terms, and several centimeters of machine table movement was controlled with a nanometer order of positioning resolution. To eliminate lateral vibration caused by the TFD, an active aerostatic coupling driven by piezoelectric actuators was inserted between the TFD and the machine table. This active aerostatic coupling was also applied as a feed drive device for fine-mode positioning; in the fine mode, the positioning resolution was 50 pm. Factors influencing pico-positioning, such as how noise from displacement sensors and vibrations in the aerostatic guideway affect positioning resolution, are discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.5
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• pp.484-491
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• 2013

In this paper, the method of designing a wideband antenna has been introduced through the design technique that simultaneously employs L- and slot-type feeds. Using the two kinds of feeds and additional fence structure, a compact wideband patch antenna has been realized. The size of the patch has been reduced by about 30 % based on the low frequency(824 MHz) and the full fractional bandwidth is wider than 100 %. The L-feed element is for the EM coupling feeding at the low frequency, while it functions as a feeding line for the power coupling through the slot at the high frequency. The proposed antenna has been designed not only for wideband operations but also for a proper array element with a reduced size. Thus, the foundation for developing the ultra wideband patch array antennas has been prepared. The fabricated antenna has been found to have good characteristics on V.S.W.R and the radiation patterns over the full bands. The experimental and computed results are shown to be in good agreement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.2
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• pp.495-504
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• 1996

In this paper, series-fed mirostrip array anteenas with coupling-slots are prposed and their operating characteristics are analyzed based on analyzed based on analytical and experimental results. An accurate analysis method for the slot-coupled feed structure is based on using both circuit coupling between anteenas and full-wave analysis which use travling wave mode and non-traveling wave mode on feed line. The basis functions that used for the numerical analysis bas been determined depending upon the accuracy, convergence properties of the solution, and the computation time:The patch uses 3 EB mode, the slot uses 1PWS mode, and feeders use 5 PWS mode. Series-fed array antennas have been designed, built, and tested in a standing-wave configuration. Using the results of the full-wave analysis, the chebyshev array antennas consisting of 8 elements are designed and fabricated changing the amount excited to each array element by adjusting slot length and by the slot position relative to the feeder. Experiment results show that the series-fed array antenna designed by adjusting the slot position relative to the feeder is superior to that designed by slot length.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.7
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• pp.653-660
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• 2004

This paper presents monopole antenna with electromagnetically coupled feed and its equivalent circuit model. The proposed structure is consists of a rectangular disk-loaded monopole and a probe with rectangular spiral strip line feed. The rectangular disk-loaded monopole is represented by parallel RLC resonant circuit and the probe with rectangular spiral strip line feed is represented by series RLC resonant circuit. Therefore broad bandwidth can be achieved through electromagnetic coupling between these structures that generate two resonances within close frequency range. The antenna with electrical dimensions of only 0.075λ$\sub$0/${\times}$0.075λ$\sub$0/${\times}$0.075λ$\sub$0/ has 16.5 % fractional bandwidth for VSWR$\leq$2 at a center frequency of 2.038GHz.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1899-1901
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• 2001

본 논문에서는 3차원 feed horn 안테나를 볼로미터에 결합함으로써 감지도(Detectivity)를 향상시킨 비가시광 영상 감지 소자를 제안하였다. Feed horn 안테나의 우수한 지향성(Directivity)를 통해서 주위의 잡음 성분을 제거함으로써 감지도의 향상을 확인할 수 있었다. 안테나와 볼로미터와의 결합 손실을 줄이기 위해서 볼로미터의 흡수층의 모양을 원형의 형태로 하였으며 크기도 안테나 폭과 일치를 시켰다. 또한 열적 고립 구조를 만들기 위한 지지 다리의 모양도 원형의 형태로 하여서 전체 길이를 증가 시켰으며 이로 인해 열전도도(Thermal conductance)를 $4.65{\times}10^{-8}$[W/K]까지 낮출 수 있었 다. 설계된 소자의 감지도는 $2.37{\times}10^{9}$[$cm\sqrt{Hz}/W$]을 나타내었으며 안테나 결합을 통한 감지도의 향상을 확인 할 수 있었다. 볼로미터의 제작은 MEMS 기술을 이용한 표면미세가공(Surface micromachining)법으로 열적 고립 구조체를 제작할 수 있으며 3차원 feed horn안테나는 SU-8이라는 음성 감광제를 경사회전노광시켜서 제작할 수 있다.