Internal small-size antenna design for mobile phone applications

A compact internal small-size antenna for LTE band is designed. The proposed antenna is positioned on a small board space of 15×24.5mm² on the system circuit board and provides two operating bands to cover LTE700 (704MHz-787MHz) and PCS1900/UMTS2100(1850MHz-2170MHz) for the Tri-band operation on the mobile phone. The proposed antenna is based on a planar inverted F-antenna (PIFA) with a coupled feeding structure. The coupled feeding structure helps the antenna to have broadband characteristic which includes some commercial service bands. The total size includes system circuit area and non-ground area within 118×58×1.2mm³. Simulation resultsincluding S11, radiation patterns and current plotsare presentedin this paper to demonstrate that this antenna is potentially suitable for small and slim mobile devices or other wireless terminalapplications.