Near-Field Control of Handset Antennas Based on Inverted-Top Wavetraps: Focus on Hearing-Aid Compatibility

In this letter, it is shown that inverted-top wavetraps, which are quarter-wavelength-long resonators, can be used to control the near-fields of a mobile terminal antenna. The local reduction of the near-fields is especially important for the operation of the hearing aid of the user. The reshaping of the near-fields may also enable reduced specific absorption rate (SAR) values.