Super directive compact antenna design using spherical wave expansion

This contribution presents a method for the design of super directive compact antenna arrays and parasitic antenna arrays based on spherical wave expansion. The optimization procedure has been derived starting from the maximum directivity formula demonstrated by Harrington (D = N² + 2N) and has been applied for the optimization of a three- and a five-element compact antenna array of 0.4λ₀×0.25λ₀ constant maximum size. A maximum directivity of 10.4 and 14.5 dBi has been obtained by full-wave simulations in excellent agreement with theoretical results.