• Journal of Advanced Navigation Technology
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• v.14 no.3
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• pp.351-357
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• 2010

This paper proposes the adaptive class-E power amplifier with maintaining high power added efficiency (PAE) to apply RFID and wireless communication system. This switch mode amplifier is used a microprocessor to control a resonator circuits and to maintain high efficiency in case of input frequency variation. To validate the adaptive amplifier operation, which is a 450MHz operating frequency and a 100MHz bandwidth, the class E amplifier is implemented. As a result, the adaptive amplifier is maintained above 60% efficiency in frequency range and has a 74.8% maximum efficiency.

• Journal of Advanced Navigation Technology
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• v.14 no.2
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• pp.176-182
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• 2010

This paper proposes that an inverse class-E amplifier is used a tunable parallel resonator at output port in order to maintain a high power-added efficiency(PAE) and output power with wide frequency ranges. A tunable circuit has a constant Q factor at operating frequency ranges and because of using varactor diode, the inductor and capacitor values of resonator can be changed. Also, the inductance value for zero-current switching (ZCS) is implemented a lumped element and the capacitance value is made a distributed element for phase compensation. The inverse class E amplifier using tunable parallel resonator is obtained to deliver 25dBm output power and achieve maximum power added efficiency(PAE) of 75% at 65-120MHz frequency ranges.

• Progress in Medical Physics
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• v.16 no.3
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• pp.155-159
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• 2005

As a part of implantable device in body, a transcutaneous energy transmission system has been developed. It would be desirable to tansfer electrical energy to implantable devices transcutaneously. The distance between transcutaneous transformer windings are approximately equal to the thickness of the human's skin, nominally between 10$\~$20 mm. Class-E resonant amplifier is used to drive a primary coil for high efficiency. Maximum current is above 50 mA at any frequency. The developed system shows that the circuit operates correctly at each frequency; 500 kHz, 1 MHz and 4 MHz.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.673-675
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• 2010

This paper proposes the adaptive class-E power amplifier with maintaining high power added efficiency (PAE) in 400MHz range. This amplifier is used a microprocessor to adapt a resonator circuits and to maintain high efficiency in case of input frequency variation. To validate the adaptive amplifier operation, which is a 450MHz operating frequency and a 100MHz bandwidth, the class E amplifier is implemented. As a result, the adaptive amplifier is maintained above 60% efficiency and has a 74.8% maximum efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.3
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• pp.132-139
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• 1984

This paper presents an exant analysis of the class E tuned power amplifier with a shunt inductor. The following performance parameters are determined for optimum operation with any switch duty ratio: the collector current and voltage waveforms, the peak values of collector current and voltage, the output power, the power output capability, and the values of the load network elements. The analysis shows that the maximum power output capability occurs at a duty ratio of 50 percent. The measured collector efficiency of experiments is 93 percent with 0.93W at 1MHz. This amplifier is especially applicable at portable transmitters because its colletor efficiency is extremely high.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.935-940
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• 2016

Recently, wireless power transmission system is gradually extended to technology in various fields such as lighting field, electric vehicles and smartphones wireless charging system. The largest of the two elements for high transmission efficiency of the wireless power transmission system are resonant coils and power amplifiers. In this paper, in order to build a high efficient wireless power transmission system, we introduce the resonance coil manufacturing method and high efficiency power amplifier design method that operates at 6.78MHz.

• Journal of Biomedical Engineering Research
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• v.16 no.4
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• pp.447-456
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• 1995

As a part of electro-mechanical totally implantable artificial heart (TIAH) program, a transcut- aneous energy transmission system has been developed. By mutual magnetic induction between the first coil on the skin and the subcutaneously implanted second coil, the system transfers elctrical power through the skin. This research aimed at minimizing the size of the implanted part as well as maximizing the transfer efficiency. Using class I amplifier, we achieved above 75% power transfer efficiency at average 40W power transfer level which is required for normal TIAH operation. In vivo performance of the developed system and bio-compatibility of the material used in Implanted parts were evaluated through animal experiments.

• Progress in Medical Physics
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• v.19 no.1
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• pp.42-48
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• 2008

Bio-implantable devices such as heart pacers, gastric pacers and drug-delivery systems require power for carrying out their intended functions. These devices are usually powered through a battery implanted with the system or are wired to an external power source. This paper describes an inductive power transmission link, which was developed for an implantable stimulator for direct stimulation of denervated muscles. The carrier frequency is around 1MHz, the transmitter coil has a diameter of 46mm, and the implant coil is 46mm. Data transmission to the implant with amplitude shift keying (ASK) and back to the transmitter with passive telemetry can be added without major design changes. We chose the range of coil spacing (2 to 30mm) to care for lateral misalignment, as it occurs in practical use. If the transmitter coil has a well defined and reliable position in respect to the implant, a smaller working range might be sufficient. Under these conditions the link can be operated in fixed frequency mode, and reaches even higher efficiencies of up to 37%. The link transmits a current of 50 mA over a distance range of 2-15 mm with an efficiency of more than 20% in tracking frequency. The efficiency of the link was optimized with different approaches. A class E transmitter was used to minimize losses of the power stage. The geometry and material of the transmitter coil was optimized for maximum coupling. Phase lock techniques were used to achieve frequency tracking, keeping the transmitter optimally tuned at different coupling conditions caused by coil distance variations.