• Slot line

Some key features of the propagation process can be disclosed from **Figure 15** with/without a reference to the original magnitudes in **Figure 14**. Specifically, the main cluster transferring from the source through the slot line path in the þ*l* direction corresponds to the A cluster/ledge in **Figure 15(a)**. In the propagation process, time response of the impulse signal to the slot line structure forms the B or B<sup>0</sup> cluster. In detail in **Figure 15(b)**, negative potential of the B cluster shows that the vector direction corresponding to the B cluster is opposite to that of the A cluster. The A (and B) clusters reflected at the slot line open end form the C cluster propagating back to the source, and the C-cluster reflection at the source position creates the E cluster. A part of scattering energy at the slot line open end of the A (and B) cluster forms EM flow traveling along the end edge (*x* ¼ 60 mm, in the þ*y=* � *y* direction); this is scattered again at the lateral edge, and a part of scattering energy propagates back to the open-end position and the source, forming the D cluster.

*Near-Field Propagation Analysis for Traveling-Wave Antennas DOI: http://dx.doi.org/10.5772/intechopen.100856*

### **Figure 15.**

*(a) The vector magnitude signals and (b) the curve normal/surface normal vector component signals of the EM fields on the edge of the slot line versus time and versus distance from source l in the analysis band of 0–60 GHz.*
