What happened to millimeter wave communications? It is often described as synonymous with 5G, but barely any of the brand new 5G networks make use of it. In this episode, Erik G. Larsson and Emil Björnson discuss the basic properties of millimeter waves, whether it is the long sought “holy grail” in wireless communications, and where the technology stands today. To learn more, they recommend the articles “Antenna Count for Massive MIMO: 1.9 GHz versus 60 GHz” (https://arxiv.org/pdf/1702.06111.pdf) and “Massive MIMO in Sub-6 GHz and mmWave: Physical, Practical, and Use-Case Differences” (https://arxiv.org/pdf/1803.11023). Music: On the Verge by Joseph McDade. Visit Erik’s website https://liu.se/en/employee/erila39 and Emil’s website https://ebjornson.com/