| 摘要 |
PROBLEM TO BE SOLVED: To provide a 2-band circulator and isolator that is used for a dual band radio terminal equipment. SOLUTION: A magnetic field applied to a ferrite whose circularly polarized wave permeability isμ2 is controlled by a current supplied to a coil 6 as a current path. Then the 2-band circulator and isolator that is operated for two different frequency bands is realized in one package. Moreover, an operating turning direction of each band is differentiated to provide a degree of design freedom to a radio terminal equipment. A ferrite 2, a center conductor 3 and matching capacitors 4 (4-1-4-3) are used in common, and a hybrid structure consisting of a permanent magnet 5 and an electromagnet having the current path whose direction is variable is adopted. Thus, the magnetic field is controlled. The 2-band circulator and isolator whose rotating direction differs from each band is realized by utilizing the difference between the permeability at a low magnetic field and a high magnetic fieldμ'+ andμ- at a magnetic resonance point of the ferrite.
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