Design of a Broadband High Flatness Drive Amplifier Based on GaAs Process

In the RF front-end system, the drive amplifier require high flatness in the bandwidth. To adhere to the application requirements of the RF front-end circuit integration, miniaturization and high efficiency, based on the traditional theory of the drive amplifier and equalizer, this paper presents a design method to match the input impedance of the drive amplifier. This ensures that the matching network not only accommodates impedance matching but also enhances in-band flatness. To verify the reliability of this method, we developed a compact, high flatness drive amplifier utilizing the GaAs pHEMT process. The device operates in a frequency range of 2-6 GHz and covers WiFi, satellite and radio positioning. The small-signal gain is 23.5± 0.1dB, and both the input and output return loss are less than −12dB. Large-signal test reveal that the saturated output power of the whole broadband is greater than 22.5 dBm, and the corresponding power-added efficiency is greater than 34%. The test results demonstrate enhanced flatness compared to the traditional drive amplifiers.