High Spatial Resolution Magnetic Probe for Near Field Measurement

Recently, all the electrical device frequency becomes higher and higher in order to enable electronic products have better performance and become much faster such as CPUs, cellphones, smart watches...etc. Almost all the products you can see around yourself contains electronic circuit. With generations of Internet of things(IOT) coming, electronic products will everywhere in our lives in the near future. It also means that the circuit in integrated circuit (IC) and printed circuit board (PCB) must become shorter and shorter. With the size of PCB and IC shrinking, measurement in near field system becomes more and more difficult due to the limitation of the magnetic probe resolution. Thus, we reduce the width of the probe and build the model in ANSYS HFSS to see the resolution. (Fig.1. is our simulation structure in ANSYS HFSS) However, according to Faraday's law, with the area of sensitive loop reducing, the induced electromotive force must be decreased. In a near field measurement system, we usually connect a low noise amplifier (LNA) on the top of the magnetic probe, and the inductance signal of the probe must to be large enough (At least greater than the dynamic range of the LNA) for a LNA to be recognized. All in all, we have to find the balance between resolution and inductance.