A Figure of Merit for Losses in Printed Reflectarray Elements

This letter describes the effect of ohmic and dielectric losses in printed reflectarray elements. An RLC lumped-element model is derived, where the values of the parameters are obtained via a full-wave analysis of the structure in few frequency points. This model permits a wide-band representation of the frequency response of the reflectarray element, which is in excellent agreement with the full-wave simulations. On the basis of this model, a figure of merit related to losses is defined, which permits to compare in a systematic way the performance of elements with different shapes.