Interband Frequency Distortion Suppression in a Dual-Band Power Amplifier Via Analog Predistortion

Nathan Biesterfeld, Taylor Barton and Will Sear, Department of Electrical and Computer Engineering, University of Colorado Boulder, 425 UCB, 1111 Engineering Drive, Boulder, CO 80309

This work presents an approach to linearizing a dual-band power amplifier via an analog predistortion resonating filter. Undesirable interband frequencies are introduced to the output signal by the nonlinear power amplifier. These may be corrected by appropriately filtering the input signal in the digital or analog domain, a method known as predistortion. Digital predistortion is commonly implemented for conventional single-band power amplifiers operating on signals with one dominant frequency component. However, predistortion for newer, dual-band power amplifiers operating on signals with two distinct frequency components is less investigated. Dual-band power amplifiers are a research topic of interest because they are better able to meet the needs of modern telecommunication systems where wider bandwidths are critical (e.g. 5G). Unfortunately digital predistortion of a dual-band signal is significantly more computationally expensive, so it is desirable to linearize the output via an analog filter. The analog filter will account for nonlinearities introduced by the power amplifier to minimize the amplitude of the interband frequency component of the output. To suppress the interband frequency component, a predistorting transfer function will be determined based on the known response of a dual-band power amplifier. Network synthesis techniques will be applied to this transfer function to realize an RF filter from distributed components. The filter will be designed for and tested with a 10 watt S-band dual-band power amplifier. If successful, the filter will increase the ratio of the carrier amplitude to the interband amplitude of the output signal. This corresponds to improved linearity of the dual-band power amplifier in dual-band operation.

Additional Abstract Information

Presenter: Nathan Biesterfeld

Institution: University of Colorado at Boulder

Type: Poster

Subject: Electrical & Computer Engineering

Status: Approved

Time and Location

Session: Poster 6
Date/Time: Tue 2:00pm-3:00pm
Session Number: 4540