A 135 GHz 32 Gb/s Direct-Digital Modulation 16-QAM Transmitter in 28 nm CMOS

This paper presents a 135 GHz direct-digital modulation 16-QAM transmitter employing a Cartesian architecture with separate phase and amplitude modulation. The transmitter, implemented in 28 nm CMOS, demonstrates a peak output power of 0 dBm. A maximum data rate of 32 Gb/
$s$
is achieved using 16-QAM without any equalization or pulse shaping. Star-QAM and QPSK modulations lead to data rates of 27 Gb/
$s$
and 24 Gb/
$s$
, respectively. The transmitter consumes 130 mW of DC power.