mmWave antenna systems: 256-element arrays, EIRP regulations

Large-Scale Phased Array Architecture

mmWave base stations use phased array antennas containing 256 or more radiating elements arranged in a rectangular grid. Each element is a tiny patch antenna only a few millimeters across at 28 GHz, connected to its own phase shifter and sometimes its own power amplifier. By controlling the relative phase of signals fed to each element, the array creates highly directional beams that can be steered electronically without any mechanical movement. The array gain increases proportionally with the number of elements. A 256-element array provides approximately twenty-four dBi directional gain,…