Effect of antenna bandwidth and placement on the robustness to user interaction

Modern smart phones require antenna systems that can deal with an ever-growing number of bands. This study compares two different approaches to the coverage of large bandwidths: Wide-band (WB) antennas covering a whole band at once and tunable narrow-band (NB) antennas covering only one channel at a time but tunable to all channels within the band of interest. To investigate the effect of antenna placement the antennas are placed both at the top and the bottom of the phone. All antenna configurations are simulated in talk position with a head and hand included. The hand is constructed with a movable index finger and the index finger is swept at 6 positions on the backside of the phone. The study shows that WB antennas detune a lot more than NB antennas and that top-mounted antennas are experiencing more than 6 dB higher losses than bottom-mounted antennas. It is proposed to expand this study with more antenna types and placements as both of these parameters are known to influence the immunity to the user. It is also proposed to compare the simulation results to measurements to increase the confidence in the results.