Microwave Theory

Whenever electrotechnical systems are no longer small in relation to the wavelength, the usual approximation of the simultaneity of the network or field variables in the system can no longer be assumed; instead, wave propagation effects must be taken into account. Traditionally, high-frequency effects are used, for example, in radio systems for communication and radar. However, due to the high clock frequencies of processors, they must also be taken into account in the development of digital circuits. Steep switching edges in frequency converters can also cause high-frequency effects in the supply lines and windings of electrical machines. Finally, they even occur in energy transmission networks with standard network frequencies, for example if the length of the transmission lines is long.
The lecture first introduces this extended approach and creates an understanding of when it must be applied in order to adequately describe processes in different disciplines of electrical engineering. Methods are derived from the complete model that allow the essential aspects of wave propagation to be described more simply, even in the case of complex systems. This is used to develop components and systems which are made possible solely by high-frequency effects and which are elementary components of, for example, measurement, communication and radar systems.Classical analytical-mathematical derivations are supplemented by network and field calculation programs, as they allow a visualization of wave propagation phenomena on the one hand and are increasingly used in the development of high-frequency systems on the other.

The lecture forms an important, previously missing foundation for the specialization in communications engineering and will therefore serve as preparation for the lectures Electromagnetic Wave Propagation and Antennas. In addition, it will allow a future focus on the signal theoretical aspects in the lecture Fundamentals of Communications Engineering. As a useful basis for all specializations and a preview of the specialization in communications engineering, this lecture is part of the “4 out of 8” compulsory elective area in the fourth semester of the Electrical Engineering B. Sc. degree program.