Comparative study of different approaches to analyze unit cells of reflectarray antennas

Abstract

We present a comparative study of reflectarray antenna analysis using two different techniques. Two different reflectarrays are simulated, with an isoflux pattern and with a squared-cosecant pattern in elevation and sectored-beam in azimuth. Each antenna is analysed using two techniques to obtain the reflection coefficients matrix. Both techniques are based on the Floquet theorem assuming local periodicity. First, we use the commercial software HFSS to analyze reflectarray cells based on two stacked rectangular patches. The finite element method of HFSS is employed. The second method is an in-house ad hoc method of moments (MoM). In all cases, each reflectarray element is analyzed considering the real angle of incidence instead of the common approach of using normal incidence curves. Results show good agreement between the two approaches for the computation of the reflection coefficients as well as for the prediction of both the copolar and crosspolar components of the radiation patterns.