A new project initiated by Google (who else?) restores glory and respect to those who pioneered millimeter-wave radio and were forced to make room for the DC-and-microcontroller generation of  electronic designers ruling the scene today. So you know: your fantastic cellphone emits waves of 35-odd cms most the time (.8 to .9 GHz); and your WiFi kit, 23 or so cms (2.4 GHz). That’s still ‘DC’ to the few wizards on the globe working with millimeter waves i.e. at frequencies in the hundreds of GHz. The down side of EHF: range limited to line of sight. The glorious advantage: you can transmit gigabits of data per second at speeds up to 40 times faster than modern 4G LTE. That is, if you use phased-array antennas aimed right up, that’s right, to the sky... to keep the path loss acceptable. Compared to earlier experiments with high-altitude drones, gliders, and balloons, a solar-powered aircraft (or a cluster of these) is more versatile and reliable. Google is currently testing the technolo...