Comparative study of space-mapping-based techniques for microwave design optimisation

Space mapping (SM) has been used in microwave engineering for some 17 years and demonstrated as one of the most efficient simulation-driven design techniques available to date. By exploiting a fast and physically based surrogate model, SM allows rapid optimisation of an electromagnetic-simulated structure of interest (fine model). Several variations of SM algorithms have been proposed including input, output, implicit and frequency SM, as well as recently introduced tuning space mapping (TSM). However, TSM is an invasive technique that requires modification to the designable structure under consideration (i.e. the `cutting` and inserting of the tuning ports). Here, for the first time, a comparative study of various SM and TSM algorithms is carried out. Advantages and disadvantages of these techniques are discussed and illustrated through design examples. Recommendations for potential users of SM and TSM are given.