A 2.6GHz broadband LDMOS Doherty Power Amplifier for Small-Cell Applications

This paper presents the design approach, realization, and measurement results of a 10W fully-integrated 2way Doherty Power Amplifier (DPA) for small-cell applications. The two stage PA MMIC was designed using LDMOS technology, fabricated with a size of $3 \times 3.3$ mm$^{2}$ and mounted in a $7 \times 7$ mm$^{2}$ LGA package. To meet our efficiency requirements, a 2-way asymmetrical DPA topology was selected. Using a pulsed continuous wave (CW) signal at 2.6GHz, the fabricated DPA achieves a 45-47% power-added efficiency (PAE) at 9dB output power back-off (OBO), a linear gain of 30dB and a peak power of 40dBm. In addition, thanks to the video bandwidth (VBW) optimization, the device shows strong linearity performances by achieving an adjacent channel leakage ratio (ACLR) after digital predistortion (DPD) better than -56dBc for 200MHz instantaneous bandwidth (IBW) and up to -49dBc for 400MHz IBW.