NIST Unveils "All-in-One" Robotic Millimeter-Wave Antenna Test Facility

Along with it comes mm-wave antennas and greater challenges in testing. Gone are the days when antenna calibration for far-field characterization revolved around football-field-size installations and towers tens of meters tall. By the 1960s, antenna testing for near-field measurements moved indoors; those results could then be extrapolated to real-world far-field values. Properly testing today's antennas requires measurements at thousands of positions, each accurate to within one-hundredth of a wavelength. For signals at 183 gigahertz (the emission line for atmospheric water vapor absorption), which have a wavelength of 1,638 micrometers, the probe must be within 33 μm of its ideal position in every dimension on every measurement.