Skyrocketing demand for high data throughput in modern wireless communication systems is leading to the use of high peak-to-average-power-ratio (PAPR) signals. This situation poses a challenge to RF power-amplifier (PA) designs for future mobile communication systems. The Doherty PA (DPA) has been widely adopted in base-station infrastructure due to its excellent ability to maintain high efficiency over an extended power range.1 As a result, DPA bandwidth has become a research hotspot.
In recent years, many efforts have taken place to expand the bandwidth of the DPA. Ref. 2 presents a new configuration for designing broadband DPAs that involves employing a post-matching network and low-order impedance inverters. Furthermore, a novel combiner represents a non-negligible method for implementing broadband DPAs.3, 4 In Ref. 3, it was shown that adding a shunt LC tank at the drain of the peaking transistor improved the DPA’s bandwidth.