A Novel Dual Band Transmitter for Wireless LAN IEEE 802.11a/g Applications with Digital Predistortion Linearization

Sung Min KANG
Jae Hong CHOI
Kyung Heon KOO

Publication
IEICE TRANSACTIONS on Communications   Vol.E89-B    No.7    pp.1987-1993
Publication Date: 2006/07/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.7.1987
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Devices/Circuits for Communications
Keyword: 
frequency doubler,  linearization,  microwave transmitter,  power amplifier,  wireless LAN,  

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Summary: 
A novel dual band transmitter module for 2.4 GHz and 5.8 GHz wireless LAN applications with adaptive digital predistortion linearization is presented. The module operates either as a power amplifier for 2.4 GHz or frequency doubler for 5.8 GHz band. Amplification gain is 12.9 dB at 2.4 GHz and multiplication gain is 3.3 dB at 5.8 GHz. At 2.4 GHz band, the second harmonic is about 36.5 dB lower than the fundamental, and the 2.9 GHz fundamental signal is 20.3 dB lower than the second harmonic output at 5.8 GHz operation. An adaptive digital predistortion scheme is proposed to linearize the 2.4 GHz amplifier, and to get the proper 5.8 GHz band wireless LAN signal. The 2.4 GHz amplifier with predistortion satisfies the ACPR mask requirement for the input 1 dB compression power of 5 dBm and the linearized frequency doubler shows 26 dB ACPR improvement at 11 MHz offset from center frequency by using the proposed predistortion linearization. The frequency doubler output spectrum with predistortion does meet the IEEE standard Tx mask.