UCLA

The development of materials and communication theories in the past several decades has led to more possibilities in power amplifier design and applications. In this thesis, a broadband power amplifier with power-added efficiency (PAE) between 25% to 48% (within the band of 3.3 GHz to 8.5 GHz) with a 12 V direct-current (DC) power supply and 32 dBm output power is implemented. The power amplifier consists of two single-stage gallium nitride (GaN) high-electron-mobility transistor (HEMT) amplifiers and two Marchand Baluns (balanced-unbalanced) for input and output matching. The amplifying stages have 25 Ω source impedance and 100 Ω load impedance for optimal PAE performance. The Marchand Baluns are based on two λ/4 short-circuit stubs connected to the balanced ports and a λ/2 open-circuited stub for the unbalanced port. One challenge in the Marchand Balun design is accommodating the impedance environment and ensuring close to 50 Ω source and load impedance at the input and output ports of the entire power amplifier module.