Frequency Dependent Behavior of Microstrip

Recently there has been considerable interest in the use of the open microstrip geometry as a transmission line in microwave integrated circuits. This form of propagating structure is applicable to a monolithic approach on a semiconductor substrate as well as to a hybrid approach using a ceramic substrate. In order to choose suitable materials, we have investigated the basic properties of microstrip and its interactions with the substrate. A detailed experimental investigation has brought to light two important aspects of circuit design with microstrip. First, microstrip has an upper frequency limit and second, it is dispersive.