Internal ultra-wideband slot antenna with a stepped ground plane

This article presents an ultra-wideband antenna design useful for the internal application in compact mobile devices. If is a planar circular slot antenna fed by a 50-Omega coplanar waveguide line through a circular patch. The antenna ground plane was bent and vertically connected to the system ground plane. such fabrications make the whole ground plane like a step. The modified ground plane preserves the original ultrawide bandwidth (from 2.3 GHZ to larger than 20 GHz.) and radiation characteristics from the integration with the RF circuitry. Also, the experimental results indicate that the proposed antenna call be employed in very close proximity to the possible shielding metal cases for battery and associated RF circuitry, with almost no degradation ill the antenna performances. (c) 2008 Wiley Periodicals, Inc.