Fourier-Domain DAC-based Hybrid Transmitter for Wireless Communication in 28 GHz 5G bands

This paper presents a Fourier-Domain digital-to-analogue converter (FDDAC) based transmitter (Tx) implemented using off-the-shelf components. The proposed Tx generates a signal with a coherent modulation bandwidth of up to 100MHz at a carrier frequency of 2.4GHz. The utilised DACs sampling rate is reduced by up to two orders of magnitude compared to conventional Txs. Moreover, the FDDAC approach provides intrinsic spectral shaping of the digital input signal leading to high spectral purity omitting the requirement of a dedicated signal processor in terms of oversampling and filtering. The output of the FDDAC-based Tx is upconverted to mmW-5G frequency bands by a fully integrated mixer. It provides up to 13.3dB conversion gain while occupying only 0.33mm2 of chip area in a 65nm CMOS technology. The EVM for a 16QAM signal at 2.4GHz is measured to be 9% where the upconverted band provides an EVM of 12.8%.