Configurable Independently Tunable Linearizer for Doherty Power Amplifiers

In this letter, a linearization solution for Doherty power amplifiers (DPAs) based on independently tunable linearizer (ITL) is proposed. The ITL for DPA (DITL) is obtained by vector synthesis of two parallel ITLs; the back-off and gain characteristic is configurable to match the DPAs. To verify the method, a prototype is designed at 3.5 GHz. A DPA with 8.5 dB back-off and 20-MHz wideband signal stimulated is measured, the results show that the adjacent channel power ratio (ACPR) is improved from -32.3 to -44.9 dBc, and the power consumption and cost with performance improvement is comparable to conventional linearizers. The DITL can achieve good performance without codesign with DPA, which is suitable in 5G communication system.