A 300 W Si-LDMOS Doherty PA for 700–950 MHz LTE applications based on a compensated output network design

In this paper we present a novel approach to the design of output combiners for Doherty PA (DPA). It is based on the compensated transmission line equivalence principle, applied to both the impedance inverter and the peak amplifier matching network considered as a whole. This technique is applied to the design of a Silicon Laterally Diffused MOS (LDMOS) DPA with optimized peak power and efficiency for LTE application in the 700 MHz to 950 MHz bandwidth. The approach permits the wideband absorption of the main and peak devices capacitance and the package parasitics. The fabricated prototype is characterized by a LTE signal with 20 MHz bandwidth and Peak to Average Power Ratio (PAPR) of 7.5 dB and features an average drain efficiency between 37 and 46%, with average power of 49 dBm across the band.