Wide percentage bandwidth microwave filter network and method of manufacturing same
First Claim
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1. A thin-film microwave filter including at least one stage, each stage comprising:
- a substrate including a groundplane on a first side and a first metal plate on a second side that is opposite to said first side;
a dielectric layer deposited over said first metal plate on said second side of the substrate;
a T-network of capacitors formed by a second and a third metal plate each on the dielectric layer and each entirely within an area defined by projecting the boundaries of said first metal plate normal to the groundplane wherein said first metal plate shields said second and third metal plates from said groudplate; and
at least one inductor formed primarily on the dielectric layer and connected to the T-network of capacitors.
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Abstract
A high percentage bandwith microwave filter network, according to an embodiment of the present invention, comprises a T-network of capacitors implemented with thin-film techniques by applying a groundplane to one side of an alumina substrate and a first plate to the other side. A silicon nitride dielectric layer having a high density of capacitance is deposited over the first plate, and then a second and third capacitor plate are deposited on the dielectric over the first plate.
29 Citations
6 Claims
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1. A thin-film microwave filter including at least one stage, each stage comprising:
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a substrate including a groundplane on a first side and a first metal plate on a second side that is opposite to said first side; a dielectric layer deposited over said first metal plate on said second side of the substrate; a T-network of capacitors formed by a second and a third metal plate each on the dielectric layer and each entirely within an area defined by projecting the boundaries of said first metal plate normal to the groundplane wherein said first metal plate shields said second and third metal plates from said groudplate; and at least one inductor formed primarily on the dielectric layer and connected to the T-network of capacitors. - View Dependent Claims (2, 3, 4)
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5. A method of fabricating a thin-film microwave filter, comprising the steps of:
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depositing a groundplane on a first side of an alumina substrate; depositing a first metal layer on a second side of said alumina substrate and forming said first metal layer into at least one metal plate and at least one metal jumper; depositing a silicon nitride dielectric layer over said metal first plate and jumper; depositing a second metal layer over said silicon nitride dielectric layer and forming second and third metal plates on said dielectric layer such that a T-network of capacitors is formed among the first through third metal plates; and forming at least two portions of an inductor in said second metal layer such that the two portions electrically connected to said first metal layer through said metal jumper to operate as an inductor and electrically connected to said T-network of capacitors. - View Dependent Claims (6)
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Specification