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Robotically Enhanced Antenna Laboratory for Metrology (REALM)

Researchers in large anechoic chamber with NIST logo on wall looking at robotic arms and equipment.

NIST’s antenna calibration facility features robots that help position the antennas, including those used in 5G systems. This composite photo shows preparations for calibration of a reference antenna (gold horn on the platform under the robotic arm at right) used in research by the 5G mmWave Channel Model Alliance.

Credit: NIST

The REALM specializes in robotics-based approaches that develop state-of-the-art antenna and free-space electromagnetic measurement techniques. Anchored by three six-axis industrial robot arms based on our lab’s pioneering Configurable Robotic MilliMeter-wave Antenna (CROMMA), it fosters metrological innovations for next-generation radio frequency and millimeter wave antenna systems. The capabilities of REALM address measurement and calibration challenges across a wide range of applications, from communications to remote sensing. 

REALM evolved from CTL’s pioneering Configurable Robotic MilliMeter-wave Antenna (CROMMA) system and now represents an expansive sub-discipline of antenna metrology. REALM supports research for a wide array of applications, including fundamental antenna metrology, 5G and 6G wireless, smart robotic antenna measurements systems, Over-The-Air (OTA) Testing, remote sensing, optical spatial metrology and antenna alignment, robotic kinematic calibration, and bi-static free-space material metrology. 

REALM engages with antenna standards development and the BIPM-CIPM Mutual Recognition Arrangement (CIPM MRA) framework through which National Metrology Institutes demonstrate international equivalence of their measurement standards and the calibration and measurement certificates issued. REALM is home to the long-standing internationally recognized NIST Antenna Special Test Calibration Service, which provides antenna calibrations to external customers. 


Facility Details:

REALM consists of two multi-robotic systems for performing a variety of free-space radio frequency measurements covering a range of approximately 0.1 GHz to 500 GHz. Designed to support measurements at lower frequencies from 0.1 GHz to 50 GHz is the Large Antenna Positioning System (LAPS), which consists of two 6-axis serial robotic arms and a precision 8-meter linear positioning rail. The CROMMA, a 13-axis laser-guided hybrid parallel-serial robotic system, is well adapted for high millimeter-wave frequencies over the frequency range of approximately 50 GHz to 500 GHz. 


  • Antenna pattern, polarization, and gain metrology.
  • Antenna calibration techniques.
  • Antenna measurements for 5G and 6G wireless.
  • Antenna standards development.
  • Bidirectional reflectance measurements of materials.
  • Broad band antenna calibration and testing methods development.
  • Precision non-contact optical antenna alignment techniques
  • Over-the-airir testing.
  • Robotics for antenna measurements.
  • Robotic antenna measurement system design.
  • Robotics kinematic calibration for advanced high precision high accuracy antenna positioning and scanning.

CROMMA specs


Created June 9, 2016, Updated January 31, 2024