Near-Field Gain Estimation of a Dipole Antenna in a Tissue Equivalent Liquid at 3–6 GHz for SAR Probe Calibration

The conformity assessment of a wireless communication device can be performed by measuring the specific absorption rate (SAR) at frequencies ranging from 100 kHz to 6 GHz. SAR probe calibration plays an important role in the conformity assessment based on SAR. However, SAR probe calibration using a waveguide is limited by the frequency due to the waveguide aperture dependence on the frequency. To solve this drawback, the reference antenna method was proposed for SAR probe calibration. In this study, the near-field gain of the reference antenna for SAR probe calibration was estimated on the basis of distance characteristics at 3– 6 GHz. The estimation result was compared with the result based on the coaxial probe method. Two curves of the estimated distance characteristic of the near-field gain are in good agreement with each other. This fact leads to the possibility of SAR probe calibration using the reference antenna method.