• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.1
• /
• pp.13-20
• /
• 2015

Existing LDMOS power amplifier that used class-AB and doherty system shows 55% of efficiency in 60MHz narrow band. Because RRH has been applied to power amplifier at base station. It is required that over 100MHz expanded band and more than 60% high efficiency power amplifier. In this paper we designed class-J power amplifier using LDMOS FET which has over 60% high efficiency characteristic in 200MHz. The output matching circuit of designed class-J power amplifier has been optimized to contain pure reactance at second harmonic load and has low quality factor Q. As a measurement result of the amplifier, when we input continuous wave signal, we checked 62~70% of power added efficiency(PAE) in 2.06~2.2GHz including WCDMA frequency as a 10W class-J power amplifier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.3
• /
• pp.276-282
• /
• 2015

Until recently, power amplifiers using LDMOS were Class-AB and Doherty type, and showed 55 % efficiency for narrowband of 60 MHz bandwidth. However, owing to the RRH application of base stations power amplifier module, a bandwidth expansion of at least 100 MHz and high efficiency power amplifiers of at least 60 % power efficiency are required. In this study, a Class-J power amplifier was designed by optimizing an output matching circuit so that the second harmonic load will contain a pure reactance element only and have broadband characteristics by using GaN HEMT. The measurements showed that a 45 W Class-J power amplifier with a power added efficiency of 60~75 % was achieved when continuous wave signals were input at 1.6~2.3 GHz, including W-CDMA application.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.28 no.2
• /
• pp.105-112
• /
• 2017

In order to satisfy the diffusion of multimedia service in mobile communication and the demand for high-speed communication, it is essential to modify and improve high efficiency, wideband and nonlinear characteristic of multiband power amplifier. This research is designed to implement a single-stub matching circuit as a 2nd harmonic one that meets conditions of the Class-J power amplifier. Low characteristic impedance of the single-stub line is necessary to suit conditions of wideband Class-J. This research uses ceramic substrates having high permittivity to implement the single-stub line with low characteristic impedance, which eventually results in an amplifier satisfying the output impedance terms of Class-J in wideband frequency range. This result attributes to use of GaN HEMT packaged with a 2nd harmonic matching circuit and external fundamental circuit. The measurement results of the Class-J amplifier confirms the following characteristics: more than output power of 50 W(47 dBm) in bandwidth of 1.8~2.7 GHz(0.9GHz), maximum drain efficiency of 72.6 %, and maximum PAE characteristic of 66.5 %.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.10 no.8
• /
• pp.945-952
• /
• 2015

Power amplification device which is matched to $50{\Omega}$ in order to achieve a high efficiency of a power amplifier using a GaN power amplification device, since there is a limit of application frequency bands, output power, efficiency characteristics selection, in this study based on the measurement data through the source/load-pull test, high output power and to extract quantitative input and output impedance that matches the design objectives of high output power, high efficiency, an implementation of the high efficiency power amplifier. Implemented power amplifier is shows 25watt(44dBm), PAE of 66-76% characteristics in the frequency band of 2.7-3.1 GHz.