ADJUSTMENT OF ELECTROMAGNETIC FIELDS PRODUCED BY WIRELESS COMMUNICATIONS DEVICES

摘要

Methods and apparatus are provided for adjusting the electromagnetic fields produced by telephones or other mobile devices capable of wireless communication. A wireless communication device includes a substrate having a ground plane. An antenna is coupled to the ground plane, and electrical currents are produced in the ground plane during operation of the antenna. A switchable counterpoise circuit that includes a conducting element and an inductor in series is provided on the substrate. The switchable counterpoise is selectively coupled to the ground plane based upon an operating mode of the wireless communications device, thereby adjusting the electrical currents flowing in the ground plane when the counterpoise is active. The changes in the ground plane currents can produce adjustments in the electromagnetic fields produced by the device, thereby improving hearing aid compatibility (HAC) of the device.