Wave propagation characteristics impedance characteristic

It is made clear that the so-called inductive characteristic of a grounding impedance is caused, in many cases, by the inductance of a current lead wire used in the measurement. The wave propagation characteristic on the electrode is determined by the soil permittivity in a VHF region, but is determined by in a lower-frequency region, where p is the soil resistivity and f is the frequency. Although the characteristic impedance of an electrode is proportional to In where r is the electrode radius, h the buried depth, and x the length, the effect of is more pronounced. 

Earth-return impedance has been well discussed, and its effect on the wave-propagation characteristic and the transient waveform is well-known, as is clear from a number of publications. Earth-return admittance [8,9,39,40], however, is neglected in most studies on wave propagation and surge characteristics, and its significant effect is not well understood [8,9,40, 41, 42 3]. 

Ametani, A., Y. Miyamoto, and N. Nagaoka. 2004. Semiconducting layer impedance and its effect on cable wave-propagation and transient characteristics. IEEE Trans. Power Deliv. 19(4) 523-531. 

The electromagnetic plane wave propagation is shown in Fig. 1 having a characteristic impedance within free space. 

When the acoustic waves move into the boundary of the propagation media, acoustic impedance determines basic characteristics such as reflection or transmission. Referring to Figure 33.1, if Zp is the acoustic impedance of the piezoelectric element, is the acoustic impedance of air, Z is the acoustic impedance of the acoustic matching layer, and d is the thickness of the acoustic matching layer, acoustic impedance matching conditions can be represented by (33.2), with thickness being represented by (33.3) [3]. 

---