Hybrid Analog/Digital Continuous Class B/J Mode for Broadband Doherty Power Amplifiers
- Resource Type
- article
- Authors
- Sujata Ghosh; Karun Rawat
- Source
- IEEE Access, Vol 7, Pp 74986-74995 (2019)
- Subject
- Broadband DPA
digital phase compensation
continuous mode
high efficiency
back-off
Electrical engineering. Electronics. Nuclear engineering
TK1-9971
- Language
- English
- ISSN
- 2169-3536
80282474
In this paper, a new digitally driven two input continuous mode Doherty power amplifier (DPA) architecture is proposed along with an analytical-based generic output combiner network design methodology. The load combiner provides the designer a choice to meet the optimum performance for any arbitrary back-off as well as for saturation. The PA's performance is further optimized with digital input splitting. To verify the proposed theory, a 20-W symmetrical continuous mode DPA is designed using 10-W GaN HEMTs. The proposed amplifier shows a drain efficiency between 56.0% and 75.4% at 41.4-44.6 dBm saturation power and between 45% and 56.5% at 35.7-38.5 dBm output power corresponding to 6-dB back-off. This performance is achieved over the band from 1.25 to 2.3 GHz that corresponds to 59.15% fractional bandwidth. The proposed hybrid analog/digital continuous mode DPA prototype is implemented using field-programmable gate array (FPGA)/DSP platform and qualifies the spectral mask when excited by a modulated long term evolution signal along with digital predistortion.