Читать книгу Introduction To Modern Planar Transmission Lines - Anand K. Verma - Страница 140

The characteristics of EM‐wave propagating on a planar line are strongly dependent on the nature of the materials used in planar technology. The familiarity with the characteristics of the medium and EM‐wave propagation in the unbounded medium is important to understand the working of the planar transmission lines. These topics are extensively covered in several books [B.1–B.15].

Broadly speaking, the present chapter covers basic electrical characteristics of the material media and the EM‐waves propagation in the unbounded dielectric media – both isotropic and anisotropic. In the first part of the present chapter, and also in chapter 6, attention is paid to the physical processes and the circuit models to understand the electrical properties of the material medium. The electrical and magnetic properties of the materials appear as the responses to the electric and magnetic excitations. Such excitations could be in the form of the circuit sources, such as the voltage and a current source. It could also be in the form of the field sources, such as the electric field intensity (E) and magnetic field intensity (H). The excitation could be any of three forms, namely (i) time‐independent, i.e. the static or DC type; (ii) frequency‐dependent, i.e. the time‐harmonic dependent, or AC (phasor) type; and (iii) arbitrary time‐dependent, i.e. the transient type. The discussion is limited to the static and time‐harmonic type of responses of the materials, i.e. the material response and behavior in the frequency‐domain.