Compact representation of radiation patterns using vector spherical mode expansions

A vector spherical mode expansion (VSME) method, extended from the scalar spherical mode expansion (SSME), is presented to study the radiation properties of an arbitrarily shaped antenna structure. The important difference between VSME and SSME is their expansion coefficients, which have essentially different properties. Numerical results show that VSME coefficients converge rapidly, while still yielding accurate data with a minimum number of modes.<>