OTA Near-Field Measurement Approach for Electrically Steered Antenna Arrays

Antenna arrays are an increasingly vital part of modern communications and radar applications. Over-the-air (OTA) measurements and radiation characteristics are crucial to ensure their quality, interoperability, and regulatory compliance. In modern systems where antennas and beamforming networks are integrated into a single package, OTA measurements are often the only viable option as traditional methods of characterizing the radio frequency (RF) signal separately are not feasible. In this article, we introduce an innovative near-field (NF) measurement technique that solves multiple challenges of state-of-the-art OTA measurement systems. In particular, our system is very compact, fast, and reproducible as it does not involve any relative movement of the antenna under test (AUT) or the probe antennae, making it cost-effective especially in large-scale characterization and production test scenarios. We discuss the theory and algorithm, which yields the same quantities we could get from state-of-the-art measurement systems, the design of the NF probing system, and show results from a proof-of-concept implementation that prove the possibility of reconstructing far-field (FF) antenna patterns from NF measurements under various conditions. It is important to note that while our approach facilitates large-scale and high-volume testing, it requires an initial calibration using classical antenna pattern measurement systems.