This paper presents a multi-band power amplifier by using Benzocyclobutene inductor and tunable barium strontium titanate capacitor to achieve high quality (Q) factor to improve narrow bandwidth in tunable of power amplifier. The proposed power amplifier employed two stages with resistive shunt feedback at the input stage to provide a broadband gain and steady wideband input matching. Tunable frequency range from 0.89 GHz to 2.1 GHz is conducted by tunable BST capacitor from 1 pF to 20 pF. The tunable power amplifier achieves high power gain, good input and output matching, low power consumption and good power added efficiency over all frequency range of interest. It can be concluded that the proposed multi-band power amplifier is quite promising for future mobile terminals application.
