Copy of Understanding Technical Requirements for Sub-THz Emission Measurement Compliance

Question: 

What are the technical requirements and compliance considerations for performing sub-THz emission measurements on devices operating above 95 GHz, as outlined in FCC guidance?

Answer: 

Sub-THz emission measurement requirements ensure accurate and repeatable EMC assessments up to 750 GHz, as mandated by the FCC’s Spectrum Horizons Order. This is critical for advanced communication and imaging devices, where small emissions at extremely high frequencies can cause interference or non-compliance. The FCC sets 750 GHz as the upper limit based on standard waveguide capability, extending testing into the decimillimetric (300–750 GHz) range.

To meet this requirement, existing millimeter-wave methods are extended beyond prior limits (e.g., ANSI C63.10 and KDB 842590) using the 800303 guidance. This demands specialized equipment and procedures to manage severe path loss, atmospheric absorption, and extreme sensitivity to vibration and alignment. Anti-vibration tables, precision antenna positioners, and environmental monitoring become essential to preserve measurement integrity.

For engineers and labs, this translates into upgraded facilities, expanded accreditation scopes, and rigorous documentation of setup stability, environmental conditions, and calibration. These measures ensure emissions data reflect actual device behavior, enabling defensible compliance and reliable real-world performance in the sub-THz spectrum.