Angular sampling, Test Signal, and Near Field Aspects for Over-the-Air Total Radiated Power Assessment in Anechoic Chambers

TL;DR

This paper explores over-the-air measurement techniques for Total Radiated Power in 5G mmWave systems, addressing sampling, antenna configuration, and near-field measurement challenges in anechoic chambers.

Contribution

It introduces methods to optimize angular sampling and beam sweeping for accurate TRP assessment and investigates near-field electric field measurements for TRP evaluation.

Findings

Sparse sampling can reduce measurement points without losing accuracy.

Beam sweeping improves worst-case TRP estimation.

Near-field measurements can be effective for TRP assessment.

Abstract

5th Generation Mobile Network Systems(5G systems) operating in milli-meter Wave (mmW) bands will employ base stations with integrated Active Antenna Systems (AASs) capable of beam-tracking using narrow beams obtained from array antennas encapsulated in a chip-like device. Regulatory limits for unwanted Radio Frequency (RF) emissions are currently set in terms of Total Radiated Power (TRP). As measurements at the antenna connectors are not possible, Over-The-Air (OTA) methods for TRP of unwanted emissions are needed. The method investigated here uses power density measurements on a spherical surface in an anechoic chamber. Two major challenges with such a method are: need for large number of angular points, and search for worst case antenna configuration per frequency for electrically large devices at high frequencies. These challenges are addressed by investigating the impact of correlation, sparse sampling, and use of beam sweeping on the TRP estimate. Finally, it is investigated how and in which spatial regions near-field tangential electric field measurements can be used to assess TRP.