Using a Coned Cable to Simplify the Accurate Numerical Dosimetry of a Resonant Exposure Setup Operating at 1710.2–1989.8 MHz

Abstract

A coned cable was designed for simple and accurate numerical dosimetry of a resonant exposure setup using the finite-difference time-domain (FDTD) method. A WR-430 waveguide cavity was fabricated, operating in the GSM 1800 and 1900 bands, and holding two T25 flasks with cell monolayers parallel with the $E$ -field or $H$ -field at the $H$ -field maxima. The conventional method extracted the field at a wave port to calculate the return loss ( $\vert S_{11}\vert$ ) and set the incident power ( $P_{\text {incident}}$ ), and then evaluated the specific absorption rate (SAR) in the cell monolayers. The proposed method evaluated the SAR by calculating $\vert S_{11}\vert $ and setting $P_{\text {incident}}$ at a lumped port in the coned cable optimized in the structure and dielectric property. Between the two methods, the averaged $\vert S_{11}\vert $ difference across the GSM bands of interest was less than 0.5%, and the maximum SAR difference over the cell monolayers was less than 2.5%. Compared to the conventional method, the proposed method saved the computational time by 15%–29% and significantly reduced the computational complexity in postprocessing the simulated data. The coned cable achieved the same dosimetry accuracy as using a wave port, but kept the computational efficiency and simplicity of using a lumped port.