w is the perfusion by blood (mL/g/s), and Qm is the heat generated by metabolism

(W/m3). The term Tcore represents the core, or arterial, temperature of the body. The term

in front of the temperature change is (T-Tcore) is referred to by some as B with the same

units. The conversion from w to B is

ρ

wc

B =  blood    blood

6000

The SAR in the tissues is used as the sole external heat source for generating the

temperature rise in this approach. The tissue cooling is solely from blood flow.

For this work the Visible Human body data was used in one millimeter resolution

for the head and hand as shown in Figure 1. The Remcom software Varipose was used to

position the hand so that the fingers and base of the palm are touching the phone. All

body data below the neck and wrist were eliminated from the simulations. The tissue

dielectric parameters were obtained from measured data of Gabriel[15] and the thermal

parameters were from Collins [14] and Bernardi [11]. The phone model operates at two

bands, 900 and 1800 MHz, and was derived from Bernardi [11].  The head model has

been rotated to put the phone in a realistic position touching the cheek.

Simulations were performed with Remcom's XFDTD Version 6.4 simulator for

the head and phone with and without the hand on the phone at 900 and 1800 MHz. The

SAR data, including 1 and 10 gram averages, were saved as well as the temperature rise

data. The observed data were the values and locations of the peak 1 and 10 gram SAR

averages and the peak temperature rise.  The SAR and temperature rise values are

adjusted for input powers of 250mW at 900MHz and 125mW at 1800MHz.

Figure 1:  The human head model in 1mm resolution shown with the dual band telephone.

Comparisons in the SAR and temperature rise were made with and without the hand present on the

phone.