A Simple Method for Calculating the Sensitivity of Near-field Scanning System Based on Transfer Function

In this paper, a simple method for calculating the sensitivity of near-held scanning system based on transfer function is proposed. The near-held scanning system includes an electric or magnetic probe, cables, amplifiers and measurement receiver. The sensitivity is defined as the minimum field strength that can be detected by the system. In order to establish the relationship between the sensitivity and the effects of probe, cables, amplifiers and measurement receiver, the circuit model of the near-field scanning system is built based on the transfer function. Then, the formula for calculating the sensitivity on the basis of the transfer function of the system is given. At present, the main methods for increasing the sensitivity are increasing the loop area of the probe for magnetic near-field scanning system, and increasing the gain of amplifiers for both magnetic and electric field near-field scanning system. Therefore, the proposed method is used to calculate the sensitivity of the magnetic near-field scanning system equipped with probes with different loop areas, as well as the sensitivity of the magnetic near-field scanning system with and without an amplifier. The simulation results demonstrate the simplicity and effectiveness of the proposed calculation method.