A Phase-Modulation Phase-Shifting Phased-Array Transmitter with 10-Bit Fast-Locking Phase Self-Calibration and 0/2.5/6/12dB Power Back-Offs Efficiency Enhancement

Abstract

Increasing demands on high-data capacity accelerate developments of phased-array systems with beam steering for modern wireless applications (e.g., 5G, WiFi) [1]. RF phase-shifting phased-array transmitter (TX) (Fig. 1-top-left) offers an architecture with shared mixers in system implementation. However, since the phase shifters (PSs) are placed in the RF signal path, the non-ideality of PSs, such as gain variation and implicit nonlinearity, cannot be ignored. LO phase-shifting phased-array TX (Fig. 1-top-center) places the PSs in LO signal path with increased number of mixers, which can decease the deterioration from PSs. Nevertheless, both in RF and LO phase-shifting phased-array TXs, an extra modulator to generate the modulated IF signal from baseband is necessary. Meanwhile, additional phase calibration in such phased-array TXs is usually needed. Recently, phase-modulation (PM) phase-shifting digital polar phased-array TX (Fig. 1-top-right) is proposed to achieve direct-modulation and beam-steering, simultaneously [2]. Besides, it can decease the impact from PSs' non-ideality, due to the constant envelope of PM signals. However, the digital pre-distortion (DPD) for modulation and phase-shifting is still required.