Antenna Communication and Metrology Laboratory (ACML)
The ACML, anchored by two six-axis industrial robot arms based on our lab’s pioneering Configurable Robotic MilliMeter-wave Antenna (CROMMA) system, fosters the development of next-generation 5G wireless and spectrum sharing systems through dynamic measurements, flexible scan geometries, and high speeds. Between the newer, dual-robot range and CROMMA, the Antenna Metrology Project tests and characterizes multiple steered-beam and other antennas from ultra-high frequency (UHF, from 300 megahertz through 3 gigahertz) through the 500 gigahertz range.
The ACML’s main anechoic chamber is a fully shielded, 21-foot-high space that’s 51 feet long by 23 feet wide. One of two six-axis robots is mounted on rails, accommodating antenna separations of up to 10 meters as required for gain extrapolation measurements at “lower” frequencies (the dual-robot system is optimized for the sub-gigahertz to 50 GHz range; CROMMA is optimized for frequencies above 50 GHz).
ACML’s advantages over legacy antenna ranges include configurable geometries, fast and dynamic antenna movement, beam tracking, large payload capacity and improved dynamic accuracy and repeatability. These advantages will become increasingly critical as spectrum use expands to include higher-frequency applications and MIMO systems, which positional accuracy and scan geometry limitations make difficult to measure. The dual-robot system will support MIMO, phased-array, and other measurements, with an eye on addressing an overarching need to understand the interference problems created by ever-increasing signal density in frequencies below 50 GHz.
The NIST Broadband Interoperability Test Bed (NBIT) supports studies in wireless coexistence metrology and standards, providing a flexible work environment for CTL's Trusted Spectrum Testing Program. NBIT lets researchers understand how radar, LTE, Wi-Fi and other systems interact in an integrated environment combining large anechoic and reverberation chambers. By enabling the testing of multiple independent networks in a controlled environment, NBIT sheds light on these independent, uncoordinated systems’ ability to coexist without interference – an understanding critical to developing hardware and software capable of delivering on the promise of spectrum sharing. Unique to NBIT is the integration of a live LTE network, which enables real-world testing of this complex and increasingly ubiquitous wireless-data protocol.
The testbed consists of a state of the art 3 m quiet zone anechoic chamber, a large volume reverberation chamber, and networking infrastructure to sustain testing of full communications stack equipment. In its current form NBIT is facilitating coexistence testing of commercial off the shelf Evolved Node B (cell tower) hardware to study spectrum sharing challenges in AWS-3 and Citizens Broadband Radio Service (CBRS) deployments.
Open Area Test Site
The Open Area Test Site (OATS) is a 30m x 60m metal ground screen for EMC testing and calibration from 30 MHz to 1 GHz.