22 IEEE Antennas and Propagation Magazine, Vol. 54, No. 1, February 2012 A Novel Approach for Mobile Device Design: GA-Based Distributed Optimization to Comply with OTA, SAR, and HAC Standards X. L. Chen 1 , E. Ofli 2 , N. Chavannes 2 , and N. Kuster 1.3 1 IT’IS Foundation CH-8004 Zurich, Switzerland E-mail: Vick@itis.ethz.ch 2 Schmid & Partners Engineering AG (SPEAG) CH-8004 Zurich, Switzerland E-mail: chavanne@speag.com 3 Swiss Federal Institute of Technology CH-8092 Zurich, Switzerland Abstract The objective of this study was to investigate the cost and time effectiveness of virtual prototyping when applied to the optimization of antenna system design for mobile phones, compared to traditional development approaches. For the proposed evaluation, an enhanced commercial FDTD-based electromagnetic simulation platform, powered with GPU hardware acceleration and distributed network parallelization, was applied. Advanced genetic algorithms (GAs) were used to obtain robust antenna designs, targeting a multi-goal optimum within a minimum number of simulations. Various antenna structures, including folded monopoles, planar-inverted F, and folded-inverted-conformal antennas were considered. An optimized structure was developed in less than 24 hours, indicating the superiority of virtual prototyping over traditional design and optimization procedures for reducing costs, improving quality, and, particularly, in reducing development time. Keywords: Optimization; mobile device; antenna; genetic algorithms; parallel processing; land mobile radio equipment 1. Introduction W ith the ever-increasing demand for novel handheld wireless devices, such as mobile phones and tablet personal computers, the design cycle has to be shortened in order to reduce the product-delivery time. This introduces great challenges, as product engineers have to realize a design in a rather short timeframe, while achieving complex design requirements including compliance with over-the-air (OTA) performance, Speciic Absorption Rate (SAR), and hearing- aid compatibility (HAC) product standards. With the trend toward slimmer and smaller mobile devices, the available space for the antenna is also shrinking. Inevitably, engineers face great dificulty implementing a multi-band antenna for a mobile phone with a short chassis and a small antenna volume. In recent years, emphasis has been placed on computer-aided antenna-optimization methods [1-3]. In this article, genetic algorithms (GAs) [4] in conjunction with the Finite-Difference Time-Domain (FDTD) [5] method were employed for the design and optimization of mobile-phone antennas in a computer-aided design (CAD) environment. On the basis of an up-to-date commercial mobile-phone CAD model, three types of embedded multi-band antennas were designed and optimized within a ixed volume. The objective was to eficiently achieve optimum antenna performance for all three designs by employing a well-devised optimization approach. This article is organized in the following manner. A network distribution scheme for the genetic algorithms is irst introduced, followed by a discussion of the antenna-design concepts. Next, a description of the modeling and optimization approach is presented. The results are subsequently discussed with respect to the near-ield and far-ield performance of the optimized antenna designs. Finally, a conclusion is provided on the use of computer-aided numerical modeling for mobile- phone antenna optimization. ISSN 1045-9243/2012/$26 ©2012 IEEE