If there is one main driving force pushing 5G networks for mobile communications toward commercial reality, it is most likely the need for more radio spectrum. To attain that increased spectrum, 5G networks will use the millimeter-wave spectrum—the radio spectrum above 6 gigahertz. While that certainly broadens the number of frequencies to which these networks have access, it comes at the price of signals not navigating through buildings or other obstacles very effectively.

Overcoming this shortcoming is the job of one of the key enabling technologies for 5G networks: directional phased-array antennas. In short, they electronically steer radio waves in a desired direction. Traditionally, phased-array antennas operate by creating phase shifting in the radio frequency (RF) path to steer beams in a particular direction. Unfortunately, the RF phase shifter degrades signal quality.