1-W high linear broadband RF power amplifier with Certesian feedback for TETRA modulation [Application Notes]

Designing a high-linearity, high-efficiency RF power amplifier with wide bandwidth design is a real challenge. This article explores a technique to achieve 30 dBm output power with an adjacent channel power ratio (ACPR) of more than -65 dBc for frequency range of 800-900 MHz. A three-stage gallium arsenide heterojunction bipolar transistor (GaAs HBT) RF power amplifier with Cartesian feedback in closed-loop form is the main architecture of the design. An adaptive bias technique was used in the RF power amplifier design to achieve high linearity while preserving good efficiency.