A Si LDMOS class AB power amplifier for UMTS LTE base stations

This paper presents the design and characterization of a Si LDMOS class AB power amplifier (PA) for UMTS LTE base stations at 2.69 GHz. The design is aimed for low-cost, low-power repeaters and micro-base stations and is based on a packaged 4W Si-LDMOS transistor from Freescale. The design procedure, amplifier realization, verification and evaluation with digitally modulated signals are described in this paper. The results of the measurements are illustrated and discussed together with particular design considerations necessary for the wideband modulation used in LTE. A saturated output power of 4 W and 12.6 dB gain at 1-dB compression point with maximum drain efficiency of 44% and maximum power-added efficiency (PAE) of 39% are achieved in this work.