Calibration method improves 5G base station test accuracy

Rohde & Schwarz updates its PWC200 to provide better accuracy and wider frequency range for 5G FR1 base-station testing.

The latest software update to the Rohde & Schwarz PWC200 plane wave converter (PWC) increases measurement accuracy and refines usability based on a new calibration method. With these updates, the company extends use cases of its 5G massive MIMO base station testing solution in R&D, quality assurance and production as well as conformance testing. The upgrade widens the original frequency range of 2.3 GHz to 3.8 GHz. Frequency range now covers 1.7 GHz to 5 GHz.

In impetus for the upgrade comes from the 1-O type 5G base station, which operates at FR1 frequencies (sub 6 GHz) and have antenna arrays with integrated transceivers, lacking access to internal RF ports. Thus, engineers need to perform over-the-air (OTA) testing.

To achieve accurate OTA measurements, the antenna array signal waves must be on plane with the DUT. This area, called a quiet zone (QZ), encompasses the DUT. The PWC200 uses a phased-array antenna containing 156 wideband Vivaldi antennas, which forms plane waves in the DUT’s radiating near field. It functions as a planar-wave synthesizer and near-field scanner that performs 5G massive MIMO base station testing for real-time radiated power and transceiver measurements such as error-vector magnitude(EVM), adjacent channel leakage ratio (ACLR), and spectral emission mask (SEM) measurements in an anechoic chamber.

The software upgrade improves PWC calibration and with it the accuracy of the plane wave synthesis. This method results in three times better accuracy in magnitude and phase uniformity compared to the previous version.

The software comes preinstalled in new units while existing PWC200 units can be upgraded.