This document discusses improving the performance of power amplifiers in mobile devices using a tunable matching network (TMN). It begins by introducing the issues of impedance mismatch between power amplifiers and antennas in mobile devices operating over multiple frequency bands and environments. It then presents the design of a TMN using a π-network architecture with switches to cover 700-915MHz and 1500-2100MHz bands. The document evaluates the TMN connected to a multiband power amplifier in simulation. It finds that optimizing both the S11 parameter and transducer gain of the TMN improves output power by up to 3dB and power added efficiency by up to 10% under worst-case VSWR conditions compared to no TMN. The