A Design Strategy for Bandwidth Enhancement in Three-Stage Doherty Power Amplifier With Extended Dynamic Range

作者：Barthwal Ayushi^*; Rawat Karun; Koul Shiban K

来源：IEEE Transactions on Microwave Theory and Techniques, 2018, 66(2): 1024-1033.

DOI：10.1109/TMTT.2017.2751044

• Broadband
• Doherty power amplifier (DPA)
• efficiency enhancement
• GaN
• load modulation
• three stage

This paper presents a design strategy to enhance the bandwidth of three-stage Doherty power amplifier (DPA) with operation upto 12-dB back-off. Based on the proposed strategy, a broadband 48-W DPA is designed and implemented using packaged CREE GaN transistors. The measured drain efficiency of 50%-61.8% at 12-dB back-off and 51.9%-66.2% at 6-dB back-off is obtained over the frequency range of 600-900 MHz. Over this 300-MHz band, the drain efficiency is between 51.1% and 78% at saturation. This corresponds to 40% fractional bandwidth. The three-stage DPA is also linearized with a three carrier 15-MHz WCDMA signal with a PAPR of 10.6 dB at various frequencies within operating band and shows the output signal qualifies spectral mask specifications.

• 出版日期2018-2