Integrated-Antenna Over-the-Air Testing for Millimeter-Wave Applications: An Overview of Systems and Uncertainty

Recent wireless communication systems, including the fifth-generation communication (5G) New Radio operating in the mmWave bands, demand performance measurement using an over-the-air (OTA) test instead of using the traditional conducted methods. This article provides an overview of various OTA measurement systems to measure the integrated antenna inside a 5G-and-beyond mmWave device, including the direct far-field, indirect far-field, near-field, and mid-field measurements. By considering several significant parameters, including minimum measurement distance required, metrics that can be measured, and complexity of the electrical and mechanical components of the system, suitable OTA measurement methods for integrated antennas can be selected. Furthermore, the factors contributing to the measurement uncertainty of OTA systems based on the technical report of Third Generation Partnership Project (3GPP) are summarized and discussed. By analyzing the significant parameters of each OTA system and the contributors of the measurement uncertainty, the reader can determine the OTA method that is most suitable to measure the integrated antennas for mmWave communications.