“…By minimizing the reflection coefficient at the terminal port of the EM structure, the impedance matching between the designed EM structure and the reference point (in practical RF EH systems, the reference point is referred to the module that transforms the RF energy to DC voltage, i.e., the RF-to-DC rectifier in a rectenna system) occurs, and con-secutively, the impedance of the designed EM structure tends to reach the characteristic value of 50 Ω. In this work, we express the given optimization problem by minimizing the reflection coefficient as the system metric of the designed EM structures (objective function of the optimization problem); however, the system metrics of the impedance, the radiation pattern, and the realized gain are also considered [117,118] to extract the feasible solution of the optimization problem. During the initialization phase of the optimization process in the proposed design framework, the following parameters are applied to the MVDE algorithm: The number of function evaluations, which acts as a stopping criterion in the optimization process, is equal to 10,000, and the threshold criterion for an acceptable solution of the optimization problem is set to −10 dB.…”