New resonant composite magnetic‐field probes with high detection sensitivity and electric‐field suppression ratio

AbstractThis work proposes two differential magnetic‐field resonant probes, consisting of a U‐shaped single‐loop resonant probe (S_probe) and a dual‐loops resonant probe (D_probe). These resonant probes are composed of a pair of LC resonant circuits, a pair of strip‐lines with two outputs, two rows of via fences, and two different sensing structures (single‐loop and dual‐loops). Among them, a pair of open stubs as capacitor and shorted stubs as inductor is used to form the LC resonant circuit, via fences are utilized to suppress unwanted electromagnetic wave modes, a U‐shaped single‐loop and a pair of differential dual‐loops is used to receive the electromagnetic signal. In order to prove the rationality of the design, simulation models of the S_probe and D_probe are optimized and manufactured based on four‐layers PCBs. In addition, a near‐field scanning system with a standard 50 Ω straight microstrip line as calibration kit is used to measure and calibrate these resonant probes. The tested results indicate that these designed magnetic‐field probes could operate at 1.575 GHz and have high detection sensitivity and electric‐field suppression.