Editor´s Comments

The design of modern, practical antennas for mobile phones typically involves satisfying requirements that go beyond the straightforward operating parameters of the antenna in free space. For example, such additional requirements can include the over-the-air performance of the mobile phone in the presence of the user´s hand and head, meeting SAR (Specific Absorption Rate) standards, and meeting hearing-aid compatibility (HAC) requirements. In their feature article, X. L. Chen, E. Ofli, N. Chavannes, and N. Kuster describe the use of a commercial Finite-Difference Time-Domain (FDTD)-based electromagnetic simulation software package and the genetic algorithm to optimize the design of mobile-phone antennas to meet such disparate real-world requirements. The article begins with a description of the FDTD software´s capabilities, and the use of a genetic algorithm in such software to optimize an antenna design across a range of parameters. The optimization was parallelized using two networked computers. How the optimization method was applied to the antenna is explained. The authors then describe the cell phone modeled in the study, as well as the models used for the three types of antennas considered: a folded-monopole antenna, a planar inverted-F antenna (PIFA), and a folded inverted conformal antenna (FICA). The way these antennas were parameterized and details of the optimization approach are then explained. The optimized results of the simulations included the free-space performance of the antennas in the cell phone, the performance of the antennas in the cell phone in the presence of hand and head phantoms, the SAR for the cell phone, and the hearing-aid compatibility results. In addition to discussing what factors affected the results obtained, the authors also provide information on the number of simulations and the computational time required to produce the results. The article provides quite realistic examples of practical optimization problems faced by desig- ers of cell-phone antennas, while also providing interesting insight into the performance of the types of antennas studied in realistic cell-phone usage scenarios.