An efficient spectral domain method of moments for Reflectarray antennas using a customized impedance matrix interpolation scheme

The acceleration method to be presented is a novel interpolation of the impedance matrix elements over patch size thereby reducing the number of moment method runs needed in the parameter sweep used to generate the design curves. In the Reflectarray antenna design process, the spherical angles in the plane of incidence, formed by the unit normal vector of the ith patch and the incident ⃗k vector emanating from the feed phase center to the ith patch centroid, are unique to each and every element of the Reflectarray. Thus, each and every element demands a unique design curve. For electrically large Reflectarray antennas, say on the order of thousands of elements, this would be a tremendous undertaking using the popular commercially available tools such as HFSS or CST MWS. Even with an in-house developed code based upon the standard SDMoM algorithm, this would still require many hours and possibly days. Also, if one were given a set of requirements that must be met simultaneously, an often popular approach would be to choose global optimizers such as PSO or GA, and if the evaluation of the cost function took hours or days for each evaluation, then this strategy would be unfeasible. There exists, therefore, a strong desire to accelerate the standard SDMoM algorithm to an extremely rapid pace, on the order of seconds to minutes in lieu of hours to days. This is possible using the Z-matrix Interpolation scheme as presented in this talk.