Doherty PAs Go Broadband Using Impedance Adjustment Network (.PDF Download)

May 22, 2019
Doherty PAs Go Broadband Using Impedance Adjustment Network (.PDF)

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.