Error Vector Magnitude as a Performance Standard for Antennas in the Millimeter-Wave Era: Part 1: Metric comparisons and measurement concepts

Abstract

Millimeter-wave communication systems will rely on the large-scale deployment of wideband digital modulation schemes and highly integrated phased arrays to significantly expand the number of simultaneous connections and enable multigigabit per second wireless links. The quality of a digitally modulated signal transmitted and received by millimeter-wave phased arrays depends not only on radiated power and directivity, but also the wideband frequency response of phased array elements and linearity of embedded radio-frequency (RF) transceivers. Error vector magnitude (EVM) is a measure of the amplitude and phase distortion in digitally modulated signals that accounts for all of these effects, and it is increasingly used to characterize the system-level performance of over-the-air (OTA) links between antennas and phased arrays. This article examines the merits of adopting EVM as a performance standard for antennas and phased arrays by comparing it with other commonly applied OTA metrics and reviewing EVM measurement methods and concepts applied to time and frequency domain analysis. The sequel to this article [1] will provide a comprehensive survey of the various techniques applied by representative researchers to model, simulate, and measure EVM for OTA links between antennas and phased arrays, and reflect on open challenges for further research.