Patent ID: 7859358

Claim:
A nonreciprocal circuit device comprising: permanent magnets; a ferrite having a substantially rectangular parallelepiped plate shape including two principal surfaces opposite each other, the ferrite being arranged such that the permanent magnets apply a direct current magnetic field that penetrates the two principal surfaces of the ferrite; and a first center electrode and a second center electrode disposed on the ferrite, the first center electrode and the second center electrode being electrically insulated from each other and intersecting with each other; wherein the ferrite and the permanent magnets constitute a ferrite-magnet assembly in which the permanent magnets are disposed so as to oppose the principal surfaces of the ferrite; the first center electrode and the second center electrode are disposed on the principal surfaces of the ferrite and are wound around the ferrite via relay electrodes provided on side surfaces disposed on long sides, the side surfaces being perpendicular or substantially perpendicular to the principal surfaces; and each of the permanent magnets includes a principal surface that has the same shape as the principal surfaces of the ferrite, and portions of the permanent magnet opposing the relay electrodes are thicker than other portions thereof.