A Planar Near-Field Setup for Millimeter-Wave System-Embedded Antenna Testing

An experimental method to perform near-field measurement of system-embedded antennas is presented. The proposed approach employs two probe antennas, one fixed and one scanning, enabling to retrieve both amplitude and phase of the near field. This allows us to employ conventional near-field-to-far-field transformations, without the need to resort to phase retrieval approaches. The technique is first demonstrated on a standalone 60-GHz patch, showing the good agreement between the proposed method and a conventional (one probe) near-field characterization. Then, the method is applied to the characterization of embedded antennas operating in the 60-GHz and 94-GHz bands, and it is benchmarked with simulations and conventional far-field characterization techniques.