Rohde & Schwarz and Greenerwave capture 50 cm Ku-band SATCOM ESA antenna radiation pattern in about 30 minutes using near-field testing

Rohde & Schwarz and Greenerwave have demonstrated in joint measurements that a near-field system can capture the radiation pattern of a 50 cm Ku-band electronically scanned array (ESA) for SATCOM antennas in just about 30 minutes. The results matched simulation models within 1 dB, showing that the method can verify antenna performance quickly and reliably. For SATCOM manufacturers constrained by large chamber requirements, it offers a faster and more cost-efficient testing approach. ESA antennas have become critical components in modern satellite communications systems. Accurate knowledge of radiation patterns is essential for reliable operation across LEO, MEO and GEO orbits. However, conventional far-field measurements require impractically large chambers at Ku- and Ka-band frequencies, especially when the antenna under test (AUT) has an aperture of 50 cm or more. Compact antenna test ranges (CATR) remain large as well, and require two-axis positioning of the AUT to capture radiation patterns, making measurements time-consuming. In a recent joint measurement campaign, Rohde & Schwarz and Greenerwave achieved a breakthrough in ESA antenna testing by enabling high-accuracy near-field radiation pattern characterization while significantly reducing measurement time. Greenerwave’s innovative SATCOM user terminal is based on reconfigurable intelligent surface (RIS) technology, enabling high-performance electronically scanned antennas with lower power consumption and reduced dependence on semiconductors compared with conventional approaches. For the measurements, Rohde & Schwarz provided the R&S TS8991 OTA/antenna measurement system equipped with a conical cut positioner, together with the R&S ZNA vector network analyzer. These were used to evaluate Greenerwave’s single-aperture passive ESA antenna, which performs beamforming using RIS technology. The AUT has a 50 x 50 cm aperture and is designed for low power consumption and easy integration. Measurements covered an extended upper hemisphere up to a polar angle of 120 degrees, using 1-degree steps. Ten Ku-band frequencies were captured in a total of 32 minutes using hardware trigger functionality. The data was processed with R&S AMS32 antenna measurement software, applying the FIAFTA algorithm for near-field to far-field transformation. Compared with simulation results based on a numerical twin model and Greenerwave’s CATR measurements, the difference in peak gain or directivity was at most 1 dB and typically 0.3 dB, confirming the high accuracy of the near-field solution. Export functions also enable further analysis in tools such as CST Microwave Studio and MATLAB. The test shows that even large SATCOM antennas can be characterized quickly and accurately using the R&S TS8991 antenna test system in a near-field configuration, providing a practical alternative to large far-field chambers and CATR setups. The configuration is also applicable to antenna testing for broadband, IoT and backhaul use cases that require flexible beam control and high data rates. It can be integrated easily into laboratory environments, helping shorten test cycles and reduce development costs. Greenerwave is a deep-tech company based in Paris, Toulouse and Sophia Antipolis. As a pioneer in next-generation satellite communications user terminals, it combines reconfigurable intelligent surfaces with advanced physics-based algorithms to dynamically control signal waves in real time. Its multi-orbit, cost-efficient SATCOM terminals address demand for secure and resilient connectivity, while the company is also expanding applications of its technology into communications and sensing. Rohde & Schwarz offers a broad portfolio for testing radar, electronic warfare, satellite, navigation, guidance, military radio communications and radio monitoring systems. Its offering includes RF and microwave test instruments, turnkey systems, EMC measurement equipment, antennas and RF accessories for research and development, verification, production and field requirements in aerospace and defense.