Читать книгу Introduction To Modern Planar Transmission Lines - Anand K. Verma - Страница 166

The experimental observations on the time‐dependent electromagnetic field are described by a set of the vector differential equations, known as the Maxwell equations. These sets of equations form the fundamental laws of nature, governing behaviors of the EM‐field in free space, and also in material media. Each part of Maxwell equations shows a definite nature of the EM‐field, explored by different investigators; Faraday, Ampere, and Gauss. However, Maxwell has put them in the form of a consistent set of equations using a mathematical format called the quaternions. He has also introduced the concept of displacement current. On solving the equations, either for the electric field or the magnetic field, the wave equations are obtained for the electric and magnetic fields traveling at a velocity of light in free space. Poynting has determined the power carried by the EM‐wave. Finally, Heaviside replaced the quaternions by the vector notations and presented the Maxwell equations in the present form, i.e. in the convenient form of the vector differential equations [B.26–B.28]. Such a formulation of the electromagnetic theory has opened the grand path of modern research and investigation. So, the modern form of Maxwell equations can be truly called Maxwell–Heaviside equations. However, in this text, we use normal terminology to follow the current practice.