• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권6호
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• pp.287-290
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• 2006

A class-E CMOS RF(Radio frequency) power amplifier with a 1.8 Volt power supply is designed using $0.25{\mu}m$ standard CMOS technology. To drive the class-E power amplifier, a Class-F RF power amplifier is used and the reliability characteristics are studied with a class-E load network. After one year of operating the power amplifier with an RF choke, the PAE(Power Added Efficiency) decreases from 60% to 47% and the output power decreases 29%. However, when a finite DC-feed inductor is used with the load, the PAE decreases from 60% to 53% and the output power decreases only 19%. The simulated results demonstrate that the class-E power amplifier with a finite DC-feed inductor exhibits superior reliability characteristics.

• Journal of information and communication convergence engineering
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• 제6권2호
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• pp.154-157
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• 2008

A class-E RF(Radio Frequency) power amplifier for wireless application is designed using standard CMOS technology. To drive the class-E power amplifier, a class-F RF power amplifier is used and the reliability characteristics are studied with a class-E load network. The reliability characteristic is improved when a finite-DC feed inductor is used instead of an RF choke with the load. After one year of operating, when the load is an RF choke the output current and voltage of the power amplifier decrease about 17% compared to initial values. But when the load is a finite DC-feed inductor the output current and voltage decrease 9.7%. The S-parameter such as input reflection coefficient(S11) and the forward transmission scattering parameter(S21) is simulated with the stress time. In a finite DC-feed inductor the characteristics of S-parameter are changed slightly compared to an RF-choke inductor. From the simulation results, the class-E power amplifier with a finite DC-feed inductor shows superior reliability characteristics compared to power amplifier using an RF choke.

• Journal of electromagnetic engineering and science
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• 제11권3호
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• pp.161-165
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• 2011

In this paper, a high-efficiency DC-AC converter is used for wireless energy transmission. The DC-AC convertter is implemented by combining the oscillator and power amplifier. Given that the conversion efficiency of a DC-AC converter is strongly affected by the efficiency of the power amplifier, a high-efficiency power amplifier is implemented using a class-E amplifier structure. Also, because of the low output power of the oscillator connected to the input stage of the power amplifier, a high-gain two-stage power amplifier using a drive amplifier is used to realize a high-output power DC-AC converter. The high-efficiency DC-AC converter is realized by connecting the oscillator to the input stage of the high-gain high-efficiency two-stage class-E power amplifier. The output power and the conversion efficiency of the DC-AC converter are 40.83 dBm and 87.32 %, respectively, at an operation frequency of 13.56 MHz.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.87-90
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• 2005

High-efficiency switched-mode circuits such as the class-E amplifier are well-known in the MHz frequency range. The class-E amplifier is a type of switching mode amplifier offering very high efficiency approaching 100%. In this paper of the class-E amplifier by using pHEMT device, the design has been done theoretically and experimentally, with simulation by using the harmonic balance method using circuit simulator. The amplifier using microstrip circuit and the pHEMT demonstrate 66% power-added- efficiency (PAE) at 2.4GHz with 17.6dBm of output power.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.499-502
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• 2004

A two-stage Class E power amplifier operated at 2.44GHz is designed in 0.25-$\mu$m CMOS process for Class-l Bluetooth application. The power amplifier employs c1ass-E topology to exploit its soft-switching property for high efficiency. A preamplifter with common-mode configuration is used to drive the output-stage of Class-E type. The amplifier delivers 20-dBm output power with 70$\%$ PAE (power -added-efficiency) at 2-V supply voltage.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권2호
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• pp.68-71
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• 2006

A class-E power amplifier is designed using 0.25$\mu$m standard CNMOS technology at 900MHz and the reliability characteristics are studied with the load network. The reliability characteristics is improved when a finite DC-feed inductor is used instead of RF choke. At the one you halt, the PAE(Power Added Efficiency) decreases from 58.0$\%$ to 35.7$\%$ and output power decreases from 120mW to 74mW in power amplifier using RF choke. However, when a finite DC-feed inductor is used with load the PAE decreases from 58.5$\%$ to 54.8$\%$ and output power decreases from 121mW to 112mW. From the simulated results, the class-E power amplifier with a finite DC-feed inductor shows superior reliability characteristics compared to rower amplifier using RF choke inductor.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.250-255
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• 2018

This paper presents a method for minimizing standby power consumption in wireless power transfer (WPT) system via magnetic resonance coupling (MRC) that operates at 6.78 MHz. The proposed circuit controls the required capacitance according to operational condition in order to reduce standby power consumption. Based on an impedance characteristic of the class-E power amplifier, operational principles of the proposed circuit are analyzed. Moreover, to verify the effectiveness of the proposed class-E power amplifier, an 8 W prototype for WPT system is implemented. The measured input power of the proposed class-E power amplifier at standby condition is reduced from 5.81 W to 3.53 W.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.221-227
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• 2017

A new approach to designing a broadband and highly efficient class-E power amplifier based on nonlinear shunt capacitance analysis is proposed. The nonlinear shunt capacitance method accurately extracts optimum class-E power amplifier parameters, including an external shunt capacitance and an output impedance, at different frequencies. The dependence of the former parameter on the frequency is considered to select an optimal value of external shunt capacitor. Then, upon determining the latter parameter, an output matching network is optimized to obtain the highest efficiency across the bandwidth of interest. An analytical approach is presented to design the broadband class-E power amplifier of a MOSFET transistor. The proposed method is experimentally verified by a 140-170 MHz class-E power amplifier design with maximum added power efficiency of 82% and output power of 34 dBm.

• 한국정보통신학회논문지
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• 제9권2호
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• pp.295-300
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• 2005

본 논문에서는 블루투스 Class-1에 응용 가능한 중심주파수 2.4CHz의 2단 Class E 전력 증폭기를 설계하였다. 전력 증폭기는 고효율 특성을 위해 소프트-스위칭을 하는 Class E로 설계하였다. 증폭기 가 포함된 래치-구조의 구동증폭기는 다음단의 전력 증폭기를 소프트-스위칭 모드로 동작시키기 위해 빠른 상승시간과 하강시간의 출력신호를 만든다. 이 구조는 전력 증폭기의 효율특성을 개선시킨다. 제안한 전력 증폭기는 65.8$\%$의 전력부가효율, 20dBm의 출력전력과 20dB의 전력이득을 나타낸다.

• 한국항행학회논문지
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• 제14권3호
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• pp.351-357
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• 2010

이 논문은 RFID와 같은 무선통신 시스템에 적용할 수 있는 고 효율을 유지하는 적응형 E급 증폭기를 제안하였다. 스위치 모드의 이 증폭기는 출력의 공진기를 제어하기 위하여 MCU를 사용하였고, 이에 따라서 입력 주파수 변화에 공진기 주파수를 적용하여 고 효율을 유지하도록 하였다. 이러한 적응형 E급 증폭기의 동작을 보이기 위해서 중심 주파수 450 MHz. 대역폭은 100 MHz인 증폭기를 제작하여 이 주파수 구간에서는 60% 이상의 효율을 유지하였고, 최대 효율은 74.8%를 얻었다.