Wearable antenna with low SAR for 2.45 GHz wireless medical devices and analysis of the effect of different spacing introduced

A wearable/on-body inverted-F antenna (brick shaped antenna elements) with low SAR for wireless medical devices is presented in this paper. The antenna covers 100% bandwidth of 2.45 GHz ISM band with a return loss bandwidth of 350 MHz (from 2.26 GHz to 2.61 GHz). Geometrical parameters of the antenna are optimised using parametric analysis in CST microwave studio. The antenna has highly stable gain and stable radiation efficiency with a variation of less than 0.0124% and less than 0.196 dBi, respectively. Estimated SAR value of the antenna always remains below 0.7 mW/g that is much lower than FCC specified allowable maximum limit. Power absorbed by the patient body is almost constant within the operating bandwidth and variation is around 0.044 mW/g. Predicted SAR value becomes even lower for a larger dimensions of the patient body is considered. Impact of possible two types of spacing can be introduced between the ground plane and the patient body are presented with individual spacing ranges from 0 mm to 4 mm.