Visualization of emission from bend of a transmission line with Poynting vector and wave-number vector

In order to reduce undesirable emissions from PCBs, it is important to clarify the mechanism of emissions which occur from bends in transmission lines. We have proposed a method of visualizing Poynting and wave-number vectors that reveals the direction electromagnetic wave propagate. This ability contributes to a better understanding of the propagation mechanism that cannot be recognized from near-EM-field and far-field patterns. In this report, we visualized emissions from a bend of transmission line by using the proposed method. It is found that electromagnetic energy increases around the outside of the bend, then while most of the energy propagates along the transmission line, some of the energy goes outside the line. On the other hand, we found that the wave front of the electric field proceed straight outside without turning around the bend.