Broadband simplified SAR measurement method using solid material

Simplification of the spatial specific absorption rate (SAR) measurement method is required for mobile devices used near the human body. A simplified SAR measurement method using a lightweight phantom comprising a wave absorber has been proposed as an alternative to a liquid or solid phantom at 1,850 MHz. An electric field probe is embedded in the wave absorber phantom, and is scanned with the phantom in two dimensions. The peak spatial-average SAR is estimated by using only one observation layer in the wave absorber phantom. The validity of the proposed measurement method is verified through the standard measured results of the local SAR at 835 MHz and 1,950 MHz. Since the wave absorber has stable electrical parameters and low density, the phantom is easy to handle and lightweight. However, the amplitude error of the surface impedance of the wave absorber and liquid phantoms are not acceptable in high frequency band. To achieve the broadband measurement method, this paper presents the design of the broadband phantom composed of the solid material at from 300 MHz to 6 GHz. The electrical parameters and the size of the phantom are clarified through the electromagnetic simulation.