JPS56162501A - Isolator - Google Patents

Abstract

PURPOSE:To reduce an input and output VSWR and forward loss while holding a large backward loss, by superposing and inserting a ferromagnetic plate and a dielectric plate between the earth conductor and junction electrode of a miniature isolator of a magnetic resonance type used for the UHF band. CONSTITUTION:Over the entire reverse surface of a dielectric substrate 1 having a hole in the center, an earth conductor 3 is formed and on the top surface, a main line, an opened-terminal branch line 12, and a short-circuited-terminal branch line 13 whose terminal is short-circuited by a short-circuit conductor 30 are formed. In the hole of the substrate 1, a ferromagnetic plate 2 and a dielectric plate 6 less in dielectric constant than it are superposed and a junction electrode 4 is further provided connecting with the lines 11 and 12. The magnetic plate 2 is magnetized by an external magnet 5 at right angles to the substrate and an isolator is constituted with the main line 11 used as an input and output line. In this constitution, the dielectric plate 6 reduces the capacitance of the magnetic plate 2 and while a large backward loss is held, an input and output VSWR and a forward loss are reduced.