Asymmetrical Doherty power amplifier using ferroelectric ceramics for linearity enhancement.

A new asymmetrical Doherty power amplifier (DPA), using ferroelectric ceramics, is proposed for linearity improvement. The uneven power divider based on ferroelectric ceramics substituted for the conventional Wilkinson power divider, the uneven power divider ratio between main amplifier and peak amplifier is performed by the proposed structure, at the same time, because of the loaded ferroelectric ceramics based on Barium Strontium Titanate (BST), the phase differences between outputs of proposed divider is changed to desired by modifying the voltage of BST. Furthermore, at high power lever, the phase of peak amplifier can be modified to cancel distortion of main amplifier, so the AM-PM distortion of total DPA can be corrected by tuning voltage of BST. Compared to a conventional DPA, the third-order inter-modulation distortion of proposed DPA is reduced by 18 dB, at the same time, the PAE is also improved about 6–7%. [ABSTRACT FROM PUBLISHER]