Body Loss Modeling for Wireless Communications Standards Bands

In this paper, a study is performed to understand the human body effects on antenna´s characteristics and try to establish a model of these alterations on the proximity of the human body. Using the EM simulator CST - Microwave Studio, simulations of different dipoles covering the standards bands for wireless communications (GSM, DCS, PCS, UMTS) in close proximity of a homogenous human head model were done with the appropriate dielectric parameters for each band. Two parameters were investigated: the distance between the head and the dipole (e) and the dipole orientation referring to the head (thetas). The quality factor (Q) variation in presence of the body (head) was studied for the different bands through the variation of three parameters (F_min, F_max and F_res and Q= F_res / (F_min-F_max))*. Finally, two types of antennas (a multi-band and an UWB antenna) were measured close to the human body in different positions (head, torso and hip). The results are compared to illustrate the body influence across the different standards bands which can help in the Radio Cognitive context where frequency change is considered.