RF-engineering becomes more and more important since modern communication systems need higher data rates and therefore larger bandwidths. These can only be achieved by using high frequencies in the microwave- orr mm-wave-range. Electronic circuits may behave totally different at these frequencies as compared to much lower frequencies. E.g. since the wavelength is in the order of a few millimetres or less most of the structures are small too. The Institute of Microwave and Photonic Engineering is engaged - beside other topics - in the challenges provided by these conditions like design, measurement and characterization of circuits and components.