• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.52-56
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• 2014

In this paper, a high-efficiency power amplifier is implemented using a gate and drain bias control circuit for WPT (Wireless Power Transmission). This control circuit has been employed to improve the PAE (Power Added Efficiency). The gate and drain bias control circuits consists of a directional coupler, power detector, and operation amplifier. A high gain two-stage amplifier using a drive amplifier is used for the low input stage of the power amplifier. The proposed power amplifier that uses a gate and drain bias control circuit can have high efficiency at a low and high power level. The PAE has been improved up to 80.5%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.6
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• pp.540-547
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• 2004

In this paper, a current - mode class D(CMCD) power amplifier over 70 % power added efficiency at 900 ㎒ is designed and implemented. Based on push-pull class B structure, main power loss due to charge and discharge of output capacitance in switching mode power amplifier is minimized by applying a parallel harmonic control circuit. Experimental CMCD amplifier with 73 % power added efficiency at 3.2 W and 72 % power added efficiency at 5 W are achieved respectively. In addition a characteristic of switching mode power amplifier whose output power is proportional to magnitude of U power is verified.

• Journal of IKEEE
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• v.25 no.1
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• pp.133-138
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• 2021

We propose a Ku-band three-stack CMOS power amplifier to enhance the output power and efficiency. To minimize the dc power consumption, the driver stage is designed using common-source structure. To obtain high output power and utilize a voltage combining method, the power stage is designed using stack structure. To verify the proposed power amplifier structure, we design a Ku-band power amplifier using 65-nm RFCMOS process which provide nine metal layers. The P1dB, power-added efficiency, and gain are higher than 20 dBm, 23 dB, and 25%, respectively, while the operating frequency is 14 GHz-16 GHz.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.5
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• pp.71-78
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• 2011

In this paper, we describe the design and implementation of a high efficiency and broad-band Class-J mode power amplifier using gallium nitride(GaN) high-electron mobility transistor(HEMT). The matching circuit of proposed class-J mode power amplifier for 2nd harmonic impedance designed to provide pure reactance alone. The measurement results show that output power of $40{\pm}1$ dBm, power-added efficiency of 50%, and drain efficiency of 60% for a continuous wave signal at 1.4 to 2.6 GHz.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.115-117
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• 2007

This paper is analyzed for DC-DC chopper performance of high efficiency added in electric isolation. The general converters of high efficiency are made that the power loss of the used switching devices is minimized. To achieve high efficiency system, the proposed chopper is constructed by using a partial resonant circuit. The control switches using in the chopper are operated with soft switching for a partial resonant method. The control switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the efficiency of chopper is high. And the proposed chopper is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed chopper is adopted with system development of high efficiency. The soft switching operation and the system efficiency of the proposed chopper is verified by digital simulation and experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.9
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• pp.589-594
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• 2016

P3HT:PCBM bulk heterojunction solar cells added with ferroelectric polymer were fabricated and characterized. By incorporating P3HT:PCBM solar cell with P(VDF-TrFE) ferroelectric additive, the power conversion efficiency was increased up to nearly 50%. Photoacoustic analysis on this phenomena was carried out for the first time. Through this study, we find that the ferroelectricity of the polymer additive plays the key role in the enhancement of the power conversion efficiency of the organic solar cell by suppressing the non-radiative recombination of charge transfer exciton more effectively.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.6
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• pp.41-50
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• 1995

A state-of-the-arts GaAs power metal semiconductor field effect transistor (MESFET) for 3.3V operation digital hand-held phone at 900 MHz has been developed for the first time, The FET was fabricated using a low-high doped structures grown by molecular beam epitaxy (MBE). The fabricated MESFETs with a gate width of 16 mm and a gate length of 0.8 .mu.m shows a saturated drain current (Idss) of 4.2A and a transconductance (Gm) of around 1700mS at a gate bias of -2.1V, corresponding to 10% Idss. The gate-to-drain breakdown voltage is measured to be 28 V. The rf characteristics of the MESFET tested at a drain bias of 3.3 V and a frequencyof 900 MHz are the output power of 32.3 dBm, the power added efficiency of 68%, and the third-ordr intercept point of 49.5 dBm. The power MESFET developed in this work is expected to be useful as a power amplifying device for digital hand-held phone because the high linear gain can deliver a high power added efficiency in the linear operation region of output power and the high third-order intercept point can reduce the third-order inter modulation.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.107-114
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• 2020

A power amplifier of 2.4 GHz ISM band is designed to implement a transmitter system. High efficiency amplifiers can be implemented as class E or class F amplifiers. This study has designed a 20 W high efficiency class E amplifier that has simple circuit structure in order to utilize for the ISM band application. The impedance matching circuit was designed by class E design theory and circuit simulation. The designed amplifier has the output power of 44.2 dBm and the power added efficiency of 69% at 2.45 GHz. In order to apply 30 dBm input power to the designed power amplifier, voltage controlled oscillator (VCO) and driving amplifier have been fabricated for the input feeding circuit. The measurement of the power amplifier shows 43.2 dBm output and 65% power added efficiency. This study can be applied to the design of power amplifiers for various wireless communication systems such as wireless power transfer, radio jamming device and high power transmitter.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.280-285
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• 2015

A fully integrated high-efficiency linear CMOS power amplifier (PA) is developed for 802.11n WLAN applications using the 65-nm standard CMOS technology. The transformer topology is investigated to obtain a high-efficiency and high-linearity performance. By adopting a 2:2 output transformer, an optimum impedance is provided to the PA core. Besides, a LC harmonic control block is added to reduce the AM-to-AM/AM-to-PM distortions. The CMOS PA produces a saturated power of 26.1 dBm with a peak power-added efficiency (PAE) of 38.2%. The PA is tested using an 802.11n signal, and it satisfies the stringent error vector magnitude (EVM) and mask requirements. It achieves -28-dB EVM at an output power of 18.6 dBm with a PAE of 14.7%.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.8
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• pp.57-62
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• 1993

In this paper, both feasible power gain and power added efficiency at the operating center frequency of 12 GHz are stressed to design a power FET with double-heterjunction structure. The variable parameters or the design are the unit gate width, the gate length, the doping density of AlGaAs, the AlGaAs thickness, the spacer thickness, the Al mole fraction, and the GaAs well thickness. The results of simulation for the FET with 1.mu.m gate length show that the power gain and the power added efficiency are 10.2 dB and 36.3% at 12GHz, respectively. An extrapolation of the relation between current gain and unilateral gain yields a 17 GHz cutoff frequency and 43GHz maximum frequency of oscillation. The calculation of the current versus voltage characteristics show that the output power of the device is about 0.62W.