Next generation 5G networks will provide reliable high-speed data linksbetween base stations and mobile devices. Base stations featuring antennaarrays with a large number of elements operating at high millimeter wave frequencies (e.g. 28 GHz) will use beam forming, i.e. shaping of the antenna’s radiation pattern into desired beam shapes, to allow efficient, targeted communication with mobile phone handsets. In the handsets themselves, the use of several small chip-integrated arrays in each device becomes feasible due to the small physical size of antennas at these high frequencies.

Spatial and material constraints make the integration of such antenna arrays into mobile phone handsets challenging. Chip based arrays may be accommodated underneath the back cover of the device, which, for high-end phones, may be made of metal or glass. A metal cover would act as a very effective shield, preventing communication entirely. Glass may allow electromagnetic energy to propagate through it, but its electrical thickness at high mm-wave frequencies may influence the array performance substantially.

This article presents an investigation into possible approaches to the design of the back cover of a mobile phone when integrating a chip-based antenna array by providing adequate scanning behavior across the frequency of interest. The methods and constraints described here will allow 5G antenna engineers to suggest mechanical and electrical designs that will work optimally to provide the efficient high data-rate connections that users require without sacrificing aesthetics and the tactile experience while handling the device.