A New High-Sensitivity Near-Field Composite Probe With Mirror Symmetry Design

In this letter, a new high-sensitivity near-field composite probe with mirror symmetry design is presented. Unlike conventional differential magnetic-field probes that can only measure a magnetic-field component, a new differential composite probe with series loops is proposed to simultaneously test electric and magnetic field components. To increase the detection sensitivity, a pair of series loops are inserted into the conventional differential loops, which form the composite probe. Note that these series loops and differential loops are connected in series, not in parallel. The equivalent circuit models on the detection loops are used to explain the operating mechanism of the sensitivity enhancement of this design. In addition, four evolutionary models are simulated, compared, and studied to verify the effectiveness of the sensitivity enhancement. Moreover, the composite probe is together simulated, manufactured, and measured to verify the design rationality. The measured results reveal that the magnetic-field sensitivities of the probe exceed –40 dB at 0.6–5.4 GHz, while the electric-field sensitivities of that are over –40 dB at 1.3–6 GHz, respectively. Therefore, the designed composite probe not only has higher detection sensitivity but also can test the electric and magnetic field components simultaneously.