Far Field EVM Characterization of Antenna Frequency Response via Full-Wave Analysis

The error vector magnitude (EVM) of a quadrature amplitude modulated (QAM) signal quantifies the degree of am-plitude and phase distortion and is often used to characterize the performance of millimeter wave active antenna arrays in modern communication systems, but the relative effects of antennas and RF integrated circuits on EVM are not easily distinguished from over-the-air (OTA) measurements. A method for determining the EVM of a single radiating element, based on the input voltage to radiated far field magnitude gain derived from full wave analysis, is presented. EVM is calculated for 16-QAM signals transmitted by a 28 GHz microstrip patch antenna along boresight to validate the method and demonstrate the influence of antenna bandwidth.