Innovative Near Field and Very Near Field Antenna Test Ranges

Near Field -Far Field (NF-FF) transformation techniques (TT), based on the knowledge of amplitude of the radiated field of the antenna under test (AUT), enable a significant reduction of the complexity (and hence of the costs) of a NF test range. Phase measurement, indeed, requires sophisticated measurement chains (VNA, stable cables), high stability of the environment (humidity, temperature), high accuracy of the positioning systems. These constraints become tighter with the increasing frequency, making the test range more complex especially when dealing with the millimeter (or smaller) wavelengths. Non-invasive behavior of photonic probes for EM field sensing allows reducing the perturbation on the measurement introduced by standard metallic probes, enabling the positioning the acquisition domain in the AUT close proximity (very NF). Hence, it can improve the signal-to-disturbance ratio, improve the interference immunity and reduce the acquisition time (or truncation error). This work proposes the design of an innovative, NF and VNF antenna test range, conjugating for the first time the advantages of phaseless NF-FF TT with the non-invasiveness of photonic sensing of EM fields.