Study of a hearing aid-compatible internal LTE/WWAN bar-type mobile phone antenna

An internal eight-band LTE/WWAN on-board printed antenna meeting the hearing air compatibility (HAC) specification of ANSI C63.19-2007 in the bar-type mobile phone is presented. The antenna is a coupled-fed inverted-F antenna directly printed on the system circuit board of the mobile phone and can generate two wide operating bands (698~960/1710~2690 MHz) to respectively cover the LTE700/GSM850/900 and GSM 1800/1900/UMTS/LTE2300/2500 operation. With the antenna disposed on the bottom edge of the circuit board and surrounded by an L-shape ground plane, the near-field strengths of the emitted electric and magnetic fields 15 mm above the acoustic output are evaluated to be in category M3 or M4 of the HAC specification. That is, the mobile phone with the embedded LTE/WWAN antenna can be treated as a hearing aid-compatible wireless device. Details of the HAC results are presented. Effects of the user's hand holding the mobile phone on the near-field emission of the antenna are also analyzed.