Space mapping optimization of handset antennas considering EM effects of mobile phone components and human body

Abstract

To meet antenna design specifications under realistic conditions, electromagnetic coupling effects between the antenna and its environment must be considered. In this work, an efficient antenna design optimization methodology that considers the influence of the human head and main mobile handset components on the antenna performance is presented. The computational optimization time is dramatically reduced by exploiting a Broyden-based input space mapping (SM) algorithm. Both coarse and fine models required for the SM algorithm are based on the finite-element method and are implemented in the same simulator; simplifying the modeling process. However, our coarse model does not consider any object of the actual operational environment. In spite of that and other simplifications applied to the coarse model, the proposed optimization scheme is able to find a solution that meets the specifications in a realistic environment by performing an extremely small number of expensive fine model simulations. Our practical illustration opens up the feasibility of using this CAD methodology to optimize other RF devices that operate in close proximity to objects that affect its desired response, as it is the case for many wearable devices.

Polynomial-Based Surrogate Modeling of RF and Microwave Circuits in Frequency Domain Exploiting the Multinomial Theorem

“…For the second example, consider the T-slot planar inverted F handset (PIFA) antenna proposed in [38]. Its geometry is shown in Fig.…”

“…The antenna design is intended to operate at the following bands: GSM900 (880-960 MHz), GSM1900 (1850-1990 MHz), UMTS2100 and WCDMA2100 (1920-2170 MHz). The structure is implemented in COMSOL by using the simulation bounding box dimensions, boundary conditions, and the meshing scheme proposed in [38]. All metals are defined as perfect electric conductors.…”

“…We can identify two types of surrogate models: physical and functional surrogates. A physical surrogate is usually implemented by a quasi-static approximation or an equivalent circuit; it can also be implemented in the same EM simulator used for the original structure under design, but using a coarse discretization [3] and removing some details of the original structure to speed up the simulation time [4]. However, these simplified and coarsely discretized full-wave EM models may exhibit numerical noise, discontinuous behavior, and nonnegligible simulation time with respect to the corresponding original fine model [5].…”

A compact planar inverted-F antenna with U-shaped strip for all-metal-shell handset application

“…Several other antennas have also been proposed in Refs. for mobile phone applications. However, as full‐metal‐shell handsets are getting more and more popular nowadays due to their better hand‐feeling and fantastic appearance, such evolution also raises a big challenge in antenna design as the metal‐shell associated with surrounding electronic components like front‐back‐cameras and telephone receiver would affect the antenna performance.…”

Advances in Optimization and Inverse Modeling Techniques for Microwave Filters

“…is an approximation of fine model optimum. In the past decade, several advances in space mapping such as aggressive space mapping [5] - [7], implicit space mapping (ISM) [27][28], output space mapping (OSM) [29] - [31], space mapping interpolating surrogates (SMISs) [30], inverse space mapping [32] - [33], have proven successful for difficult optimization problems of microwave filters.…”