Extremely Small, Wide-band Mobile Phone Antennas by Inductive Chassis Mode Coupling

A novel antenna concept for mobile terminals is presented which achieves large bandwidth at negligible extra volume by means of chassis mode tuning and optimally placed inductive coupling elements. The approach is best suited for folder-type ("clam-shell"), slider-type and similar device form factors featuring two separate but electrically interconnected chassis elements. The proposed antenna's mode of operation is discussed in terms of chassis mode resonances and equivalent circuits. Implementation and bandwidth over volume performance are illustrated by simulation results for a dual-feed penta-band antenna case study. As a practical application of high topical interest, an add-on DVB-H antenna for a folder-type phone with a measured return loss of at least 7 dB over the full UHF bands IV and V at negligible extra volume is reported