• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.5
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• pp.345-352
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• 2004

Currently, high data rate PLC(Power Line Communications), up to 100 Mbps, which use frequency bandwidth between 2 MHz and 30 MHz is investigated very hard, and commercial PLC modem for low voltage powerline network (indoor) is coming soon into communication market. For the purpose of developing a fit communication system which has little distortion of signal and attenuation, it is surely necessary to know about channel environments of powerline. Especially, the impedance measurement of the powerline and impedance matching are very important. As is known, since medium-voltage powerline (22.9 ㎸) is still working, it is not so simple to measure the powerline impedance. In our study, a portable impedance measurement equipment is developed. It consists of coupling capacitor, a drain coil and impedance matching transformer. The equipment is easily connected to medium voltage line and impedance of power line is measured using a network analyzer. Also, measurement results are used for impedance matching of PLC signal. In fact, matching transformer with several different impedances are used. The matching transformer is connected between coupling capacitor and signal port. In this paper, the developed portable impedance measurement equipment and impedance measurement results are presented. Also impedance matching technique using matching transformers will be explained. We showed the result of the improved performance by the impedance matching.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.43-48
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• 2020

The demand for stable plasma has been on the rise because of the increased delivery power amount in the chamber for improving productivity, and fast and accurate plasma impedance matching become a crucial performance measure for radio frequency (RF) power system in semiconductor manufacturing equipment. In this paper, the overall impedance matching was understood, and voltage and current values were extracted with voltage - current (VI) probe to measure plasma impedance in real-time. Actual matching data were analyzed to derive calibration coefficient for V and I measurements to understand the characteristics of VI probe, and we demonstrated the tendency of RF impedance matching according to changes in load impedance. This preliminary empirical research can contribute to fast RF matching as well as advanced equipment control for the next level of detailed investigation on embedded system based-RF matching controller.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.64-71
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• 2023

If an impedance mismatch occurs between the source and load in a Radio Frequency transmission system, reflected power is generated. This results in incomplete power transmission and the generation of Reflected Power, which returns to the Radio Frequency generator. To minimize this Reflected Power, Impedance matching is performed. Fast and efficient Impedance matching, along with converging reflected power towards zero, is advantageous for achieving desired plasma characteristics in semiconductor processes. This paper explores Impedance matching by adjusting the Vacuum Variable Capacitor of an L-type Matching Module based on the trends observed in the voltage of the Phase Sensor and Electromotive Force voltage. After assessing the impedance matching characteristics, the findings are described.

• Journal of the Semiconductor & Display Technology
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• v.21 no.2
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• pp.32-37
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• 2022

As semiconductors become finer, equipment must perform precise and accurate processes to achieve the desired wafer fabrication requirement. Radio frequency power delivery system in plasma system plays a critical role to generate the plasma, and the role of impedance matching unit is critical to terminate the reflected radio frequency power by modifying the impedance of the matching network in the plasma equipment. Impedance matching unit contains one fixed inductor and two variable vacuum capacitors whose positions are controlled two step motors. Controlling the amount of vacuum variable capacitor should be made as soon as possible when the mismatched impedance is detected. In this paper, we present the impedance matching algorithm using the phase sensor.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.113-118
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• 2009

This paper is about design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the power line communication (PLC) system. The Tchebycheff gain function algorithm is represented to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.258-262
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• 2010

This paper represents design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the broadband power line communication(BPLC) systems. The Butterworth gain function equalizer is used to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC Coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

• Journal of Sensor Science and Technology
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• v.27 no.6
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• pp.374-379
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• 2018

The piezocomposite transducer is widely used because it is highly efficient in transforming electric energy into mechanical energy, and its frequency range is broader than that of other types of ultrasound transducers. A general piezocomposite transducer is composed of an acoustic lens, impedance matching layers, piezoelectric materials, and backing layers. When an input voltage is applied to a piezoelectric material as an active material, it generates sound waves while vibrating. At that time, an impedance matching layer helps the sound waves to propagate forward while reducing the impedance mismatch that may occur at the interface between the active material and its front material. The impedance mismatch has a negative effect on the signal of an ultrasound transducer; thus, it is important to design a matching layer to overcome the issue. In this study, an optimized feature of a matching layer with gradient properties is studied. An objective function is defined to minimize both the average and the deviation of the reflection coefficients that are functions of the frequencies. As a result, an improvement in the signal characteristics with respect to the sensitivity and bandwidth is reported.

• Journal of the Korean Institute of Telematics and Electronics
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• v.13 no.1
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• pp.31-34
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• 1976

In this paper, the characteristics, especially impedance matching behavior of linearly tapered transmission line which impedance is varied linearly is analyzed. Also impedance matching of nonuniform microstrip which characteristic impedance or width of strip is varied linearly are experimentally investigated.

• Journal of the Semiconductor & Display Technology
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• v.5 no.4 s.17
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• pp.17-22
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• 2006

In the manufacturing processes of semiconductor, test process is important for quality of products. In the manufacturing process of dynamic memory, memory test is more important. So, automatic test equipment(ATE) is used necessarily. But, according to increase of speed of dynamic memory operation, the rapid test equipment is needed. Impedance matching between ATE and dynamic memory is expected to be an important problem for making a rapid test equipment over 1Gbps. According to increase of speed, inner impedance of ATE also works on important parameter for test. This paper is about the method that is for impedance matching of inner impedance and coaxial cable occurring in manufacturing of ATE. We proved effects of inner impedance by electric theory and verified the method of impedance matching using computer simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.828-833
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• 2007

A small monopole antenna with a novel impedance matching structure is proposed in this paper. The proposed antenna is designed for W-LAN(IEEE 802.11b). The antenna design concept is based on a ${\lambda}/8$ folded monopole antenna with a self-impedance matching structure. The size of the proposed antenna is smaller than the resonant length, thus the impedance at the terminal of the antenna becomes very capacitive. To compensate fur this impedance mismatching, the proposed antenna employs a novel self-impedance matching structure. The self-impedance matching structure is located on the top of the antenna; it improves the impedance matching and ultimately the efficiency of the antenna. The measured results of the proposed antenna show reasonable agreement with prediction.