ABSTRACT
This chapter reviews the state of the art of the field, focusing on nanoscale technologies for wireless on-chip communication in the millimeter-wave and terahertz bands. Wireless coupling schemes could eliminate this issue, however, at the cost of higher power consumption. A pioneering test chip implementing wireless clock distribution with on-chip antennas at 15 gigahertz was unveiled in the early 2000s. Wireless interconnects also show two main downturns with respect to the rest of alternatives: energy efficiency and bandwidth. Wireless interconnects need to provide performance, reliability, and cost figures comparable to those of the traditional wireline counterparts. The wireless plane rules can be implemented directly at the network interface that bridges the processor with the network. At the physical layer, leveraging the already-existing high density of antennas to create opportunistic beamforming schemes would increase the number of nonoverlapping channels and the efficiency of wireless links.
