The theory and practice of microwave antenna modelling

Antenna analysis can be considered as deriving either implicitly or explicitly the current distribution on a particular structure. Once this is known the radiation properties can be completely characterised. Analysis techniques do not have to explicitly derive the current as by Maxwell's equations currents and fields are directly linked and hence the current is often implied and not explicitly available. It depends on the analysis technique. One major point in antenna analysis is that the structure radiates and hence the problem is bounded only at infinity, unlike device analysis. The range of computational electromagnetics (CEM) tools now available to the antenna designer is considerable. This paper presents an overview of some of the various general purpose analysis approaches that are applicable to the design of microwave antennas, with the aim of giving some insight into the choice of technique for any particular application.