Application of Multiobjective Topology Optimization to Miniature Ultrawideband Antennas With Enhanced Pulse Preservation

This letter presents an application of multiobjective topology optimization to ultrawideband (UWB) antenna design. The design of UWB antennas is very challenging because it involves multiple design goals including miniaturization, a wide impedance bandwidth, uniform gain variation, and enhanced time-domain pulse preservation. Although topology optimization has been a popular approach for UWB antenna design, a multiobjective version that systematically copes with all the design details is critically lacking, and the early attempts have not been very successful. In this letter, we propose a Pareto-based technique for multiobjective topology optimization, showing that the proposed methodology facilitates the development of a UWB antenna with compact size, a wide bandwidth, uniform gain variation, and high fidelity factors. The optimized UWB antenna occupies a small area of 15 ×15 mm
²
, showing excellent impedance matching and stable broadside gains throughout 3.1-10.6 GHz. In addition, the variation of group delay drops dramatically from 0.94 to 0.40 ns, and the fidelity factor is enhanced from around 0.80 to 0.92. The simulated and measured results are exhibited, confirming the validity of multiobjective topology optimization.