Design of an Advanced CMOS Power Amplifier

Kim, Bumman; Park, Byungjoon; Jin, Sangsu

doi:2015.15.2.63

J. Electromagn. Eng. Sci > Volume 15(2); 2015 > Article

Journal of Electromagnetic Engineering and Science 2015;15(2):63-75.
DOI: https://doi.org/10.5515/JKIEES.2015.15.2.63

Design of an Advanced CMOS Power Amplifier

Bumman Kim¹, Byungjoon Park², Sangsu Jin¹

¹Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH)
²Division of Information Technology Convergence Engineering, Pohang University of Science and Technology (POSTECH)

Abstract

The CMOS power amplifier (PA) is a promising solution for highly-integrated transmitters in a single chip. However, the implementation of PAs using the CMOS process is a major challenge because of the inferior characteristics of CMOS devices. This paper focuses on improvements to the efficiency and linearity of CMOS PAs for modern wireless communication systems incorporating high peak-to-average ratio signals. Additionally, an envelope tracking supply modulator is applied to the CMOS PA for further performance improvement. The first approach is enhancing the efficiency by waveform engineering. In the second approach, linearization using adaptive bias circuit and harmonic control for wideband signals is performed. In the third approach, a CMOS PA with dynamic auxiliary circuits is employed in an optimized envelope tracking (ET) operation. Using the proposed techniques, a fully integrated CMOS ET PA achieves competitive performance, suitable for employment in a real system.

Key words: CMOS, Envelope Tracking (ET), Long-Term Evolution (LTE), Power Amplifier (PA), Supply Modulator