A Wideband Dual-Component Electric Probe for Near-Field Measurement

In this article, a wideband dual-component electric probe is designed for the simultaneous measurement of near-field tangential and normal electric fields. The probe has three sections, including a sensing section, a transmitting section, and an output section. The sensing section consists of two symmetric L-shaped monopoles, which can induce the electric field components in two directions. The responses are outputted to the receiving device through the substrate integrated coaxial line (SICL) in the transmitting section and the grounded coplanar waveguide (GCPW) in the output section. Through post-processing, the differential mode voltage and the common mode voltage of the two output voltages represent the induced intensity of the tangential electric component and the normal electric component, respectively. To reduce the interference of irrelevant field components and improve the calibration accuracy, the slot line is used to generate the standard tangential electric field, and the microstrip line is used to generate the standard normal electric field. Simulation and measurement results indicate that the proposed probe has a bandwidth of 4 to 16 GHz. The spatial resolution is 0.6 mm for measuring tangential electric field and 0.7 mm for normal electric field at 16 GHz. The near-field scanning results of the electric field distribution above the slot line and microstrip line demonstrate that the proposed probe can simultaneously measure two kinds of electric components efficiently.