Compact 3D-loop antenna with bandwidth enhancement for WWAN/LTE mobile-phones applications

This study presents a 3D-loop antenna for wireless-wide-area network/long-term evolution (WWAN/LTE) operation. The size is compact and low profile and so the antenna is suitable for mobile-phone applications. The loop itself generates four resonant modes. Three parasitic elements are placed closely to the 3D-meandered loop radiator to generate three more resonant modes. These resonant modes form a dual-band, a lower band and a wide upper band, to cover many current mobile standards. The antenna performance, in terms of impedance bandwidth, efficiency, peak gain and radiation pattern, is studied using simulation. The antenna is also fabricated and the prototyped antenna is measured using the Satimo StarLab system. The measured results of the antenna inside a phone case on a phantom hand and phantom head in the data mode and talk mode, respectively, (defined by the Cellular Telephone Industries Association) are also presented. The measured efficiencies are subsequently used to estimate the total-radiated powers (TRPs). Results show that the TRPs in all covered standards meet the strictest over-the-air testing requirement of Vodafone.