Simulation‐driven size‐reduction‐oriented design of multi‐band antennas by means of response features

Abstract

This study addresses the problem of explicit size reduction of multi-band antennas by means of simulation-driven optimisation. The principal difficulty of electromagnetic (EM)-based miniaturisation of multi-band antennas is that several resonances have to be controlled independently (both in terms of their frequency allocation and depth) while attempting to reduce physical dimensions of the structure at hand. The design method of choice in this work is feature-based optimisation (FBO) framework. The methodology has been shown as appropriate for handling multi-band antenna responses. The primary objective of the optimisation process is the footprint area of the antenna. At the same time, design requirements pertinent to reflection characteristics are handled by means of a penalty function approach. The properties of the FBO framework, namely ‘flattening’ of the functional landscape, allows to keep the design optimisation costs at acceptable levels of few dozens of evaluation of the EM simulation model of the antenna. For the sake of demonstration, two antenna structures are considered, a dual-band patch antenna, and a triple-band dipole antenna. Considerable size-reduction ratios are achieved, over 50% and almost 30% for the first and the second structures, respectively. Numerical results are validated experimentally.