Broad-band power amplifier with a novel tunable output matching network

A multiband power amplifier module (PAM) comprised of an InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) broad-band power amplifier (PA) and a tunable multiband output matching circuit is proposed and demonstrated. The three-stage MMIC broad-band PA is realized by using the novel HBT structure and layout, applying broad-band and compensating matching technique in matching network design, adopting power gain predistortion at the first stage, and optimizing the distribution of power gain among stages. The output matching circuit is implemented with parallel inductance-capacitance (LC) tank circuits using p-i-n diodes to control the inductor value. This multiband PAM offers advantages of tunable frequency band, low insertion loss, small size, and high linearity. The multiband PAM biased at 3.5 V demonstrates 27-dB power gain, 30-dBm output power, and higher than 40% power-added efficiency at frequencies covering dual bands from 0.85 to 0.95 GHz and from 1.71 to 1.95 GHz.