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US 4,918,410 AGranted
Isolator for microwave electromagnetic radiation
AssigneeBritist Telecommunications, Public Limited Company
InventorsAdalbert Beyer, Ingo Wolff
Life of this patent
Estimating the term…
Abstract
An insert for non-reciprocal waveguide device comprises a layer of ferrite and a layer of energy absorbing material with a spacer layer between them. The device works by reason of asymmetrical interaction of the microwave energy and the ferrite whereby energy is preferentially absorbed in the reverse direction. The spacer layer affects the distribution of electromagnetic fields so that there is a relatively low attenuation associated with one direction and a relatively high attenuation associated with the reverse direction.
Claims27
A non-reciprocal E-plane device comprising:
- waveguide means, adapted to receive microwave signals, for propagating microwave signals therethrough;
- and
- a lamella structure disposed in said waveguide means, said structure including a ferrite layer adapted to be disposed in a magnetic field, a microwave energy absorbing layer, and a dielectric spacer layer disposed between the energy absorbing layer and the ferrite layer, said layers being oriented parallel to the E-plane of said waveguide means and said dielectric layer having a dielectric constant of at least 1.5, said structure attenuating signals propagating through said waveguide means in a first direction by a first attenuation and attenuating signals propagating through said waveguide means in a second direction opposite said first direction by a second attenuation much greater than said first attenuation.
A non-reciprocal E-plane device comprising:
- waveguide means, adapted to receive microwave signals, for propagating microwave signals therethrough;
- and
- a lamella structure disposed in said waveguide means, said structure including a ferrite layer adapted to be disposed in a magnetic field, a microwave energy absorbing layer, and a dielectric spacer layer disposed between the energy absorbing layer and the ferrite layer, said layers being oriented parallel to the E-plane of said waveguide means and said dielectric layer having a dielectric constant of at least 1.5, said structure attenuating signals propagating through said waveguide means in a first direction by a first attenuation and attenuating signals propagating through said waveguide means in a second direction opposite said first direction by a second attenuation much greater than said first attenuation;
- wherein the lamella structure additionally includes a further microwave energy absorbing layer disposed between the dielectric spacer layer and the ferrite layer.
1 more element
A lamella structure comprising a ferrite layer, a microwave energy absorbing layer, and a dielectric spacer layer situated between the ferrite layer and the energy absorbing layer, said spacer layer having a dielectric constant between 1.5 and 20 and said layers being adapted for orientation parallel to a magnetic field and the E-field of propagating microwave energy so as to effect non-reciprocal propagation thereof.
A lamella structure comprising:
- a ferrite layer,
- a microwave energy absorbing layer,
- a dielectric spacer layer situated between the ferrite layer and the energy absorbing layer;
- said spacer layer having a dielectric constant between 1.5 and 20 and said layers being adapted for orientation parallel to a magnetic field and the E-field of propagating microwave energy so as to effect non-reciprocal propagation thereof;
- and
- an additional microwave energy absorbing layer situated between the ferrite layer and the dielectric spacer layer.
3 more elements
A non-reciprocal finline device comprising:
- a finline including at least one conductive layer adapted to define a conductive transmission line path for microwave energy propagation therealong, said conductive layer being supported on at least one substrate layer;
- and
- a lamella structure adapted to be disposed in a magnetic field and disposed adjacent to said finline, said lamella structure comprising:
- a ferrite layer adjacent to said finline;
- a microwave energy absorbing layer and
- a dielectric layer having a dielectric constant of at least 1.5 disposed between the energy absorbing layer and the ferrite layer, said layers being oriented parallel to the E-plane of microwave energy when propagated along said path.
3 more elements
Apparatus comprising:
- means for defining a microwave signal propagation path along which microwave energy may be propagated with a predetermined E-field orientation;
- and
- isolator means, disposed along said path and adapted to be disposed in a magnetic field, for providing high attenuation of microwave signals propagating along said path in a first direction and for providing low attenuation of microwave signals propagating along said path in a second direction opposite said first direction, said isolator means including a laminated structure having a ferrite layer, a microwave energy absorbing layer, and a dielectric spacer layer having a dielectric constant of at least 1.5, said layers arranged in a laminated stack with said dielectric spacer layer separating said ferrite layer and said energy absorbing layer, each of said layers being oriented parallel to said E-plane.
Apparatus comprising:
- means for defining a microwave signal propagation path along which microwave energy may be propagated with a predetermined E-field orientation;
- and
- isolator means, disposed along said path and adapted to be disposed in a magnetic field, for providing high attenuation of microwave signals propagating along said path in a first direction and for providing low attenuation of microwave signals propagating along said path in a second direction opposite said first direction, said isolator means including a laminated structure having a ferrite layer, a microwave energy absorbing layer, and a dielectric spacer layer having a dielectric constant of at least 1.5, said layers arranged in a laminated stack with said dielectric spacer layer separating said ferrite layer and said energy absorbing layer, each of said layers being oriented parallel to said E-plane;
- wherein said energy absorbing layer comprises a magnetically loaded epoxy resin mateial with a magnetic loss factor in excess of 0.01.
1 more element
Apparatus comprising:
- means for defining a microwave signal propagation path along which microwave energy may be propagated with a predetermined E-field orientation;
- and
- isolator means, disposed along said path and adapted to be disposed in a magnetic field, for providing high attenuation of microwave signals propagating along said path in a first direction and for providing low attenuation of microwave signals propagating along said path in a second direction opposite said first direction, said isolator means including a laminated structure having a ferrite layer, a microwave energy absorbing layer, and a dielectric spacer layer having a dielectric constant of at least 1.5, said layers arranged in a laminated stack with said dielectric spacer layer separating said ferrite layer and said energy absorbing layer, each of said layers being oriented parallel to said E-plane;
- wherein said energy absorbing layer comprises a dielectric material with a dielectric loss factor characterized by a tan (.DELTA.) in excess of 0.01.
1 more element
Apparatus comprising:
- means for defining a microwave signal propagation path along which microwave energy may be propagated with a predetermined E-field orientation;
- and
- isolator means, disposed along said path and adapted to be disposed in a magnetic field, for providing high attenuation of microwave signals propagating along said path in a first direction and for providing low attenuation of microwave signals propagating along said path in a second direction opposite said first direction, said isolator means including a laminated structure having a ferrite layer, a microwave energy absorbing layer, and a dielectric spacer layer having a dielectric constant of at least 1.5, said layers arranged in a laminated stack with said dielectric spacer layer separating said ferrite layer and said energy absorbing layer, each of said layers being oriented parallel to said E-plane;
- wherein said laminated structure further comprises a further energy absorbing layer disposed in said stack between said ferrite layer and said spacer layer.
1 more element
Dependencies are inferred from the claim text.