Reconstruction of Near-Field Millimeter-Wave Power Density from Over-The-Air Measurements

Human exposure from fields radiated by millimeter-wave devices in the close proximity from the head or body is quantified in terms of near-field free-space power density (NF PD). A new approach to assess the NF PD is introduced, based on spherical measurements at larger distances from the device under test, combined with equivalent source reconstruction. Simulations and measurements demonstrate an excellent accuracy of the technique, making it a potential candidate for future regulatory compliance evaluations. Its applicability to over-the-air scenarii is established, by involving a phase retrieval method with broadband digitally modulated signals.