Ferrite substrates for microwave integrated systems

New developments for ferrite substrates applicable to hybrid microstrip microwave circuits are described. In order to make ferrite elements an integral part of microwave systems a technique of integrated magnetic zones is presented. This technique is based on the application of "nonmagnetic" ferrites, i.e., substituted ferrites with a Curie temperature much below room temperature. Such nonmagnetic ferrite substrates will be compared with alumina substrates. The application of the new substrate technology in microwave integrated systems will be discussed.