Wave transmission lines and networks – Plural channel systems – Nonreciprocal gyromagnetic type
Reexamination Certificate
2008-10-28
2010-10-19
Jones, Stephen E (Department: 2817)
Wave transmission lines and networks
Plural channel systems
Nonreciprocal gyromagnetic type
C333S024200
Reexamination Certificate
active
07816994
ABSTRACT:
A microwave circulator uses a thin-film exchange-coupled structure to provide an in-plane magnetic field around the circulator. The exchange-coupled structure is a ferromagnetic layer having an in-plane magnetization oriented generally around the circulator and an antiferromagnetic layer exchange-coupled with the ferromagnetic layer that provides an exchange-bias field to the ferromagnetic layer. A plurality of electrically conductive ports are connected to the exchange-coupled structure. Each of the portions or legs of the circulator between the ports may have an electrical coil wrapped around it with each coil connected to an electrical current source. The ferromagnetic resonance (FMR) frequency of the exchange-coupled structure in the absence of an external magnetic field is determined by the properties of the material of ferromagnetic layer and the magnitude of the exchange-bias field due to the exchange-coupling of the ferromagnetic layer to the antiferromagnetic layer. If one or more of the optional coils is used, then the FMR frequency can be tuned by changing the current in the coil or coils to change the magnitude of the externally applied magnetic field.
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Berthold Thomas R.
Hitachi Global Storage Technologies - Netherlands B.V.
Jones Stephen E
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