Study of a complementary antenna for wearable applications

A complementary antenna for wearable applications is proposed. By introducing a loop-monopole combined structure, unidirectional beam is obtained and the interaction between the antenna and the human body can be potentially mitigated. The antenna´s operation principle is analyzed and validated at first. Then, prototypes are designed and measured. When the antenna is placed in free space, an impedance bandwidth (20log|S₁₁| <; -10 dB) from 2.76 to 8.13 GHz is obtained. When it is worn on different persons, stable impedance from 1.8-5.6 GHz can be achieved. Finally, a prototype is worn on a pork phantom and measured for its radiation patterns. It is seen stable unidirectional radiation patterns can be achieved within the whole impedance bandwidth. Therefore, the proposed antenna should be a good candidate for wearable applications.