A low profile wideband unidirectional antenna for wearable device
In this paper, a wideband wristband antenna for wearable device, characterized by low profile and unidirectional radiation property, is proposed. First, the Theory of Characteristic Mode (TCM) is employed to expound the operation principle of the generation of unidirectional radiation. Then, an appropriate feeding structure is chosen to excite the desired modes. As a result, the corresponding modes are excited and the unidirectional radiation is obtained. Moreover, the desired cellular operation bands (from 1710 MHz to 2155 MHz) are achieved. The total efficiency accompanied with flatness feature are at the levels of -1.5 dB and -6.5 dB in free space and with phantom respectively.