New Differential Probes With Low Profile and High Detection Sensitivity

In this work, two new differential magnetic and composite probes with a low profile and high detection sensitivity are proposed. First, conventional grounded and nongrounded differential magnetic and composite probes are depicted to measure double magnetic field and electromagnetic field couplings, respectively. Second, two pairs of grounded and nongrounded U-shaped loops as parasitic components are inserted into the proposed differential magnetic and composite probes to enhance the sensitivity in magnetic and electromagnetic field measurement. Notably, in order to reduce the probe’s profile, another pair of parasitic grounded and nongrounded U-shaped loops are etched on the inner layers of these probes, while another pair of grounded and nongrounded U-shaped loops are placed at the ends of the outer grounded planes, respectively. This new design is completely different from the traditional design, where the detection loop is always located in the inner layers. For the traditional design, these proposed probes require at least an eight-layer printed circuit board to manufacture. However, these proposed probes in this work only require a six-layer printed circuit board to manufacture owing to their unique design. Finally, for the purpose of verifying the outstanding feature of these designed probes, two simulated models are given, simulated, and manufactured on a six-layer printed circuit board and characterized by a standard microstrip line. The measured results reveal the magnetic field transmission coefficient of the magnetic probe is greater than −31.5 dB in the range of 2.5–10 GHz, and the electric and magnetic field transmission coefficients of the composite probe are greater than −31.7 dB in the range of 3–10 GHz and −31.6 dB in the range of 2.5–10 GHz, respectively. Therefore, these presented magnetic and composite probes have not only a low profile but also higher sensitivity, which could improve measurement accuracy and save manufacturing costs.