A 250W LDMOS Doherty PA with 31% of fractional bandwidth for DVB-T applications

Abstract

We discuss the development of a wideband LDMOS Doherty PA (DPA) with optimized peak power and efficiency over 550 MHz to 770 MHz of bandwidth. The design was enabled by a wideband output combiner which involves multisection impedance transformation. The DPA delivers more than 46% average efficiency across the band at 48 dBm average power supporting DVB-T signal with 8 MHz bandwidth and PAPR of 10.5 dB. The DPA prototype achieves the target ACPR of - 50 dBc at the upper limit of the bandwidth if digital predistortion is applied.