A Miniature Wideband Active Magnetic Probe Design With High Spatial Resolution and High Sensitivity for Near-Field Measurement

In this letter, a miniature wideband active magnetic probe with high spatial resolution and high sensitivity is designed for near-field signal measurement. The wideband amplifier and the horizontal transition structure, which is stripline (SL) to spoof surface plasmon polariton (SSPP) transition, are applied for the wide bandwidth. The loop area is designed as 0.04 mm2 to improve spatial resolution. The amplifier chip and the corresponding power circuit are integrated into the probe to enhance the sensitivity. The proposed probe is fabricated under a multilayer printed circuit board (PCB) process. The measurement results show that the bandwidth of the proposed probe is from 16 to 43.5 GHz, the spatial resolution is 0.48 mm at 43.5 GHz, and the sensitivity is much higher than that of the reference probe without an amplifier.