Fast EM-Driven Size Reduction of Antenna Structures by Means of Adjoint Sensitivities and Trust Regions

In this letter, a simple yet robust and computationally efficient optimization technique for explicit size reduction of antenna structures is presented. Our approach directly handles the antenna size as the main design objective, while ensuring satisfactory electrical performance by means of suitably defined penalty functions. For the sake of accuracy, the antenna structure is evaluated using high-fidelity EM simulation. In order to maintain computational efficiency of the design optimization process, it is carried out using cheap adjoint sensitivities and trust region framework utilized as convergence safeguard. Our technique is illustrated through a design of a compact quasi-isotropic dielectric resonator antenna and a UWB monopole. Numerical results are supported by physical measurements of a fabricated prototype.