Antenna arrays consisting of multiple radiating elements are widely used in both defense and commercial applications. The individual elements of the antenna array are usually fed with signals of different phases to form the desired radiation pattern, generally a beam or multiple beams. The beam can be steered by controlling the phase of the signals feeding each element, and the amplitudes of the signals are often optimized to minimize sidelobe radiation.
Cellular base stations widely use phase shifters to adjust the “down tilt” of the antenna, called remote electrical tilt (RET), which is used to optimize coverage and minimize interference. This enhances performance, such as increasing capacity, coverage and signal strength. The move toward sophisticated massive MIMO (mMIMO) solutions is an advanced form of beam steering, with the disadvantage that a separate radio is required for each antenna element.