Reconfigurable Hybrid Asymmetrical Load Modulated Balanced Amplifier with High Linearity, Wide Bandwidth, and Load Insensitivity
This paper presents the first-ever load-insensitive
and highly linear three-way load-modulation power amplifier
(PA) based on reconfigurable hybrid asymmetrical load
modulated balanced amplifier (H-ALMBA). Through proper
amplitude and phase controls, the carrier, control amplifier
(CA), and two peaking balanced amplifiers (BA1 and BA2) can
form a linear high-order load modulation over wide bandwidth.
Moreover, it is theoretically unveiled that once CA reaches
saturation at the pre-determined power back-off (PBO), its
current- and voltage-source duality makes the primary (BA1) and
secondary (BA2) peaking amplifiers have complementary load
dependence. As such, the PA’s linearity and efficiency profiles
can be maintained against arbitrary load mismatch through
ZL-dependent reconfiguration of CA supply voltage (VDD,CA)
and turning-on sequence of BA1 and BA2. Based on the proposed
theory, an RF-input H-ALMBA is developed with GaN transistors
and wideband quadrature hybrids.