Title :
A Wideband Envelope Tracking Doherty Amplifier for WiMAX Systems
Author :
Moon, Junghwan ; Kim, Jangheon ; Kim, Ildu ; Kim, Jungjoon ; Kim, Bumman
Author_Institution :
Pohang Univ. of Sci. & Technol., Pohang
Abstract :
We have demonstrated a wideband envelope tracking Doherty amplifier. The amplifier is implemented using Eudyna 10-W GaN high electron mobility transistor. For world interoperability for microwave access (WiMAX) signals of the 802.16d and 802.16e, the Doherty amplifier covers the 90 MHz bandwidth (2.3-2.39 GHz) of the Korea´s mobile WiMAX (WiBro). The performance of gain, power-added efficiency (PAE), and relative constellation error (RCE) are nearly uniform for the bandwidth. In order to improve the linearity, we have applied the envelope tracking technique to the gate of the Doherty amplifier. The envelope tracking amplifier delivers a significantly improved RCE performance of 35.3dB, which is an enhancement of about 4.3dB, maintaining the high PAE of about 30% for the 802.16 d signal at an average output power of 35 dBm.
Keywords :
III-V semiconductors; WiMax; amplifiers; electron mobility; gallium compounds; Doherty amplifier; Eudyna high electron mobility transistor; WiMAX systems; bandwidth 90 MHz; frequency 2.3 GHz to 2.39 GHz; microwave access signals; mobile WiMAX; noise figure -35.3 dB; power-added efficiency; relative constellation error; wideband envelope tracking; Bandwidth; Broadband amplifiers; Gallium nitride; HEMTs; High power amplifiers; Linearity; MODFETs; Microwave amplifiers; Performance gain; WiMAX; Envelope tracking; GaN; gate bias control; relative constellation error (RCE); wideband Doherty amplifier; world interoperability for microwave access (WiMAX);
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2007.912019
