ABSTRACT
This chapter presents nonlinear effects of the power amplifier (PA) as well as power-efficient complimentary metal-oxide-semiconductor (CMOS) PA. The continuous advancement of semiconductor technologies, especially CMOS technology, has enabled an exponential growth of the wireless communication industry. The chapter provides a thorough analysis of the nonlinear effects of PAs, especially a closed-form analysis of the relationship between multitone adjacent-channel leakage ratio and two-tone intermodulation distortions. Conventional modulations, such as frequency modulation, frequency-shift keying, and Gaussian minimum-shift keying have their information stored in the frequency and/or phase variations—not in the envelope amplitude, and thus do not require linear power amplification. Linearity is one of the major concerns in current and near future wireless communication systems. Radio frequency PA design involves handling large voltages and large amounts of current at radio frequencies, which in the present wireless communication standards are in the gigahertz range.
