Linearization techniques for integrated CMOS power amplifiers and a high efficiency class-F gallium nitride power amplifier

My study was on linearization techniques for integrated CMOS power amplifiers and a high efficiency GaN power amplifier. My study proposes two types of predistortion linearization circuits compatible with CMOS processes. Dynamic impedance lines of the nonlinearity generation circuits of the proposed predistorters were analyzed and the equivalent circuits of the nonlinearity generation circuit were obtained from the large signal simulation. Characteristics of the predistorter circuits were analyzed and compared. The phase distortion characteristic of the cascode CMOS power amplifier was also investigated. The predistorter circuits were fully integrated into CMOS power amplifiers. Three kinds of CMOS power amplifier were fabricated and the small signal characteristics and the large signal characteristics of the CMOS power amplifier were measured. Results showed that the third-order intermodulation distortion of the power amplifier was improved by the integrated predistorters. The developed predistorters can be applied to both the CMOS process and the compound semiconductor process. The predistorters also have low loss and low power consumption characteristics.; My study also describes a high efficiency power amplifier using a wide bandgap GaN HEMT device. The dc and ac characteristics of GaN HEMT device were measured and modeled using the Curtice cubic model. The GaN HEMT device was mounted on a high dielectric constant substrate and class F configuration was implemented at the output of the GaN HEMT device. Results showed high efficiency operation of the power amplifier using a wide bandgap GaN device at microwave frequency.