A miniature broadband antenna for portable communications terminals

Many of today\´s portable communication applications require antennas that are compact, broadband and easily integrable in a big variety of terminal geometries. A planar ultra compact antenna (diameter <0.2 /spl lambda/ and thickness <0.06 /spl lambda/) satisfying these requirements is presented. The antenna consists of two stacked circular patches creating two cylindrical slots resonating at two slightly different frequencies, fed by a strategically positioned coaxial probe. The design landmarks as well as the impedance and radiation behaviors of the novel antenna are presented. A S-band and C-band of the so-called "dime" antenna have been designed, fabricated and tested for validation and prototyping purposes. Very good agreement between numerical and experimental results has been obtained with frequency bandwidths of 10%.