A Simple Miniature Ultrawideband Magnetic Field Probe Design for Magnetic Near-Field Measurements

A simple miniature magnetic-field probe for near-field measurements in 9-kHz-20-GHz bandwidth, which is applied to highspeed circuits, has been proposed and manufactured. The magneticfield probe is built on a four-layer printed circuit board (PCB) using high-performance and low-loss Rogers material (εr= 3.48 and tan δ = 0.0037). Electric field coupling can be suppressed by PCB shielding structure of the magnetic-field probe. Coax-thru-hole via array technique is used to achieve impedance match. The resonance in working frequency band is suppressed through via fence, making |S21| rather smooth in the operation band. Experimental results show that the working frequency band is up to 9 kHz-20 GHz.