Improvement of hearing aid compatibility (HAC) of terminal antennas using wavetraps

A technique for reducing the antenna induced electromagnetic fields in the vicinity of the earpiece speaker in mobile phones is presented, thereby improving the hearing aid compatibility (HAC). By introducing resonant quarter-wave short-circuited transmission lines to each long side of the chassis edges, the earpiece speaker section of the chassis is electrically decoupled from the antenna section. The proposed technique has been validated through simulations and measurements.