A Wideband and High Sensitivity Active Near‐Field Magnetic Probe With a Horizontal Transition

In this paper, the wideband and high sensitivity active near‐field magnetic probe is proposed. The probe has three sections, including a coupling section, a transmission section and an amplifier circuit section. In the coupling section, the small loop with the process limit is designed to achieve high spatial resolution. In the transmission section, the horizontal gradual microstrip line (SL) to grounded coplanar waveguide (GCPW) transition is designed for good field and impedance matching, resulting in a wide bandwidth. A low‐noise amplifier is integrated into the amplifier section to achieve high sensitivity. The proposed probe is fabricated under the printed circuit board (PCB) process. Simulation and measurement results indicate that the operating frequency band of the probe is from 10 MHz to 8 GHz, the spatial resolution is 0.6 mm, and the sensitivity is 21.5 dB higher than that of the passive reference probe with the same size.