Contact-less RF and optical measurement of antenna array active impedance using scattering data

Antenna array active impedance is conventionally determined via direct S-parameter measurements. This approach is impossible to implement for optical nano-antenna arrays. This paper describes a technique for evaluating antenna array active impedance based on scattering measurements. This technique can also be used for optical sensor applications, since the scattering data of a nano-antenna array, loaded with unknown loads, can be used to determine the reflection coefficient of the loads. The theoretical formulation, followed by simulations and measurements demonstrate the advantages and limitations of this technique.