NASA’s Horizontal Planar Near-Field Facility: A Large-Scale, High-Accuracy System for Spaceborne Antenna Testing

NASA has commissioned a cutting-edge 10m x 10m horizontal planar near-field (HPNF) measurement facility to advance the precision characterization of space communications antennas for aerospace and defense applications. This system is designed to accommodate a wide variety of antenna types, including active electronically scanned arrays (AESAs) and parabolic reflectors, operating across an extensive frequency range of 1–110 GHz. The broad bandwidth posed significant challenges in the design of the RF subsystem as well as high positioner accuracy over the full scan plane, requiring innovative solutions to ensure measurement accuracy and reliability. This facility fills a critical need for high-fidelity antenna testing as next-generation space and defense systems demand increasingly precise performance.

A standout feature of the facility is its integration of a laser tracker, which enables precision alignment of antennas and detailed surface measurements of parabolic reflectors to characterize their shape with exceptional accuracy. Beyond standard gain and pattern measurements, the system supports advanced active antenna test modes, including effective isotropic radiated power (EIRP), gain-to-noise-temperature ratio (G/T), intermodulation distortion (IMD), and gain compression. Additionally, it offers pulsed RF capabilities to evaluate high-power-density active antennas, making it versatile for both current and emerging technologies. These capabilities ensure comprehensive performance assessments under realistic operational conditions.

The horizontal orientation of the measurement system provides a distinct advantage over vertical setups, particularly for large antennas. By allowing antennas to be mounted horizontally, the facility simplifies installation and mitigates gravity-induced deformations that can occur during vertical testing—distortions that are irrelevant in the zero-gravity environment of space. This facility is a cutting-edge tool for high-precision antenna measurements, essential for the development and validation of next-generation aerospace and defense technologies.