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

Abstract

This 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.