Magnetic field probes for time-domain monitoring of RF exposure within tissue-mimicking materials for MRI-compatible medical device testing
A new RF B/H field probe for time-domain monitoring of RF electromagnetic-radiated exposure during medical device testing inside the lossy tissue-mimicking material is presented. The probe was tuned and matched for a centre frequency of 127.6 MHz to optimise the response for testing within typical 3T MRI scanners or RF exposure platforms. A 5 mm radius loop was chosen as a trade-off between spatial resolution and sensitivity and fabricated on a double-sided FR4 PCB. In the presented scheme, a low-noise RF amplifier was employed to reduce the sensitivity of the probe to induce voltage on the transmission lines and to improve accuracy. The implemented probe was found to provide acceptable spatial resolution and sensitivity for reliable B/H field mapping for this application.
