Electromagnetic field characteristics of injection probes

The authors developed the system which could analyze the distribution of immunity level of printed circuit board (PCB) by injecting uniformly strong electromagnetic (EM) field into a local area of PCB. This system could find a lower area of immunity level in PCB effectively by making the injection area of EM field small step-by-step. For this purpose, the uniformly strong EM field had to be injected only into the area covered by the injection probe. They produced various injection probes experimentally, and the EM field characteristics were evaluated. As a result, they confirmed the following: uniformly strong EM field occurred only into the area covered by each injection probe even if the size was different; frequency characteristics of every electric field injection probe were almost the same; and strength of EM field of each injection probe became almost the same by adjusting the input level to probe. In other words, they could inject the uniformly strong EM field for an arbitrary area of PCB by changing the size of injection probe