Efficient analysis method and design approach for broadband reflect‐arrays with isotropic/artificial anisotropic substrates

Abstract

Plane-wave scattering by metallic grating with artificial anisotropic substrate is a problem solved in this study for the design of broadband reflectarrays. For determination of the reflection characteristics of such structures, a generalised transmission line modelling is used for evaluating the dyadic Green's function. This function is utilised in a summation equation used for calculating the induced electric currents on the reflectarray's metallic grating. For solving the obtained summation equation, the Periodic Method of Moments with Galerkin procedure is applied. Such an analysis method helps to compute the phase diagram needed to design of reflectarray. The efficiency of this method is assessed by considering its cost-time and rate of convergence versus space harmonics. In the design step, a new phase realisation approach is implemented for minimising the frequency dispersion's adverse effects. This approach optimises the arrangement of metallic elements on the reflectarray's aperture and decreases the dependency of broadband reflectarray design to the element phase behaviour. As a result, this technique leads to lower side lobe level and better frequency response than traditional approaches. To verify the results of the developed solution, two different broadband reflectarrays for X- and Ku-bands are fabricated and measured.