Abstract: The present research provides a high-density magnetic ceramic composition for microwave application and a preparation method thereof. The magnetic ceramic composition of this research includes Yttrium iron garnet (YIG, Y3Fe5O12) as its basic element and a little amount of additional element, silicon oxide (SiO2), which is expressed as: Y3Fe5O12+x SiO2 (0.05?x?5 mol %). The magnetic ceramic composition is prepared by measuring proper amounts of ferric oxide (Fe2O3), yttrium oxide (Y2O3) and SiO2, mixing them, calcining the mixture, and molding and sintering them. Since the magnetic ceramic composition of the present research has very little magnetic loss, it can be used in components for communication in a microwave band, usefully.

Abstract: A microstripline/stripline included in an isolator/circulator is provided. The microstripline/stripline includes a resonator including a plurality of symmetric propellers, which are capable of transmitting signals in a single direction, slot formation units formed between the propellers to allow magnetic walls to be symmetrically generated and each including a plurality of slots, transfer tracks for bandwidth expansion formed at a side of each of the propellers within the range of the distance (the circumscribed radius of the resonator) between the center of the resonator and the outermost edge of the propeller, and ports formed at the ends of the transfer tracks. The microstripline/stripline further includes a coupler for detecting a reverse signal formed at the port, to which a load resistor is connected, and an indicator for indicating the reverse signal detected by the coupler in order to detect the state of the isolator and a system including the isolator.