The level of integration of 5G base stations in the FR1 frequency range is increasing, as a new generation of base stations, designated the 1-O type, is becoming more and more common. The 1-O type base stations operate at FR1 frequency range and they have antenna arrays with integrated transceivers, without any access to internal RF ports. This requires all conformance and production testing to be performed over-the-air (OTA). However, OTA testing can be technically challenging.
For accurate OTA measurements, signal waves sent from the antenna must be plane when reaching the device under test (DUT). The area encompassing the DUT where the waves are plane is called the quiet zone (QZ). This can be achieved through a large distance between the antenna and the DUT, resulting in large and expensive shielding chambers. Rohde & Schwarz has a strong portfolio of solutions for OTA testing, designed to answer these challenges. Some of them are based on compact antenna test range (CATR) technology, where a gold-plated reflector is used to create the plane waves, allowing the DUT to be relatively close to the antenna. However, with large DUTs such as base stations, the size of the high-precision mirror would be prohibitively large and increase the price of the system considerably. With a solution based on the PWC technology in its OTA test portfolio, Rohde & Schwarz is broadening the options available to the users, especially for large DUTs.
The R&S PWC200 needs four times less space than solutions based on other OTA technologies such as CATR. The R&S PWC200 is based on a phased antenna array consisting of 156 wideband Vivaldi antennas to form plane waves within an adjustable QZ, placed in the radiating near field of the DUT. It functions as a planar-wave synthesizer and near-field scanner and is designed for 5G massive MIMO base station testing for real-time radiated power and transceiver measurements (EVM, ACLR, SEM, etc.) in a controlled anechoic test chamber environment. The R&S PWC200 features an internal RF verification solution. This makes it possible to perform precise monitoring and correction of the R&S PWC200 antenna without using an external antenna.