A 56Gb/s Zero-IF D-Band Transmitter for a Beamformer in 22nm FD-SOI

We present a transmitter (TX) suitable for a beamformer operating between 118GHz and 147GHz. The TX is one antenna path of a 4-way beamforming TRX chip: it supports up to 64QAM modulation (30Gb/s at -25dB EVM) and achieves a data rate of 56Gb/s with a 17dB EVM at an output power POUT of 3dBm using 16QAM modulation. The zero-IF TX comprises a baseband section, I/Q generation, upconverter, a PA with a PSAT of 11dBm, and a cascade of two frequency triplers for LO generation using an external LO reference. The LO beamforming scheme ensures a phase resolution of 0.1°. A single TX channel draws 232mW from a 0.8V supply and has an area of 1.17×0.3 mm² in a 22nm FD-SOI process.