A 1-Bit-DSM-Based Digital Polar Power Amplifier Supporting 1024-QAM

This letter proposes a Sub-GHz digital polar power amplifier circuit, which is intrinsically linear and power efficient. The architecture is based on a 1-bit delta–sigma modulator (DSM) to achieve amplitude modulation without a lossy capacitor array, which improves efficiency. A deskewing circuit eliminates skew-induced nonlinearity and improves the EVM without predistortion. The proposed 1-bit-DSM-based PA, integrated in a 65-nm CMOS process, achieves −36.5-dB RMS EVM and 24.1% PAE for a 10 MSymbol/s 1024-QAM modulated signal at 960-MHz carrier, without predistortion.