A novel dual band transmitter for WLAN 802.11 a/g applications

This paper presents a novel dual band P-HEMT power amplifier/frequency doubler module for 2.4 GHz and 5.8 GHz wireless LAN applications. The module operates as a power amplifier for 2.4 GHz and frequency doubler for 5.8 GHz. The transmitter module has 4.5 dB amplification gain at 2.4 GHz and 3 dB multiplication gain at 5.8 GHz frequency multiplier. At 2.4 GHz band, the 2nd harmonic is about 30 dB lower than the fundamental signal, and at 5.8 GHz band the fundamental and 3rd harmonic are 22 dB lower than the signal. The 2.4 GHz amplifier satisfies the ACPR mask requirement, and the frequency doubler output needs 10 dB ACPR improvement at 11 MHz offset from center frequency by using predistortion linearization. Matlab simulation shows the possibility of digital predistortion to satisfy the ACPR requirement.