A 20Gb/s 79.5mW 127GHz CMOS transceiver with digitally pre-distorted PAM-4 modulation for contactless communications

Contactless chip-to-chip or board-to-board proximity (~1mm) communications have been realized by using either wireless transmission [1-3], or inductive/capacitive coupling schemes [4-6]. However, their practical deployments in consumer electronics are currently limited because of bandwidth-density-inefficient OOK/ASK-only modulations [1-3], process/voltage/temperature sensitive carrier-recovery-less coherent detection [1], and large coupler footprint (6~10mm
²
) for meeting bandwidth requirements [1], [4-6]. To overcome such challenges, the demonstrated contactless communication system employs a 127GHz CMOS transceiver to concurrently increase the coupling bandwidth and reduce coupling antenna size. Furthermore, a PAM-4 modulator with digital pre-distortion (DPD) in the transmitter (TX) and an envelope detecting non-coherent receiver (RX) are designed to further scale the bandwidth and eliminate carrier recovery circuitry, respectively.