Common-Source Common-Drain (CSCD)-Based Integrated RF Power Amplifier for Wireless Communication Systems

In wireless transceivers, the power amplifier (PA) is the most power-consuming and critical component, as it must meet stringent linearity and reliability requirements while maintaining high efficiency. Traditionally, PAs are implemented using a common-source (CS) configuration. However, recent studies have explored the common-drain amplifier (CDA) as a promising PA topology, offering advantages in stress handling and linearity. Since the CDA is inherently a current amplifier, it can be integrated with a CS amplifier to form a hybrid common-source common-drain (CSCD) configuration. Despite its potential, limited research has been conducted on CDA-based or CDA-inspired PAs. This work introduces a novel approach by employing the CDA as a foundation for developing CSCD PAs, thereby opening new avenues in CMOS PA design. Using a 130-nm RFCMOS process, a CSCD amplifier is fabricated and packaged in QFN-32. The amplifier achieves a saturated output power (P ${}_{sat}$ ) of 31 dBm and a power gain of 10 dB at a center frequency of 706 MHz, with a peak power-added efficiency (PAE) of 39%. To further validate the concept, wideband 4G LTE (Long-Term Evolution) signals are applied to evaluate linearity and output power. Under a 16-QAM, 20 MHz UTRA signal, the amplifier delivers 28.1 dBm output power with an Adjacent Channel Power Ratio (ACPR) of –30 dBc and an error vector magnitude (EVM) below –30 dBc, maintaining an average efficiency of 26%. The design meets LTE performance standards, demonstrating strong potential for robust, high-efficiency RF amplification in wireless communication systems.