Near fields of phased antennas for mobile phones

Near fields of a two-element phased antenna array are studied over the phase changes. It is revealed that in the differential mode the phased array yields a cool area of near fields at the chassis end opposite to the antennas. It is further shown that the folded loop antennas exhibit similar patterns of the near fields in the differential mode. It concludes that placing differential antennas at the phone bottom is helpful to meet the hear aid compatibility (HAC) requirements.