Low loss saw filters with non-sequential coupling and method of operation thereof
AssigneeCom Dev Ltd.
InventorIan A. D'Souza
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Abstract
A low loss surface acoustic wave (SAW) filter and method of operation thereof uses non-sequential coupling and, more particularly, cross-coupling to achieve good rejection characteristics with low loss. Strips of metallization are used with a circuit formed of a thin film of metallization. The strips are oriented parallel to an edge of each resonator being cross-coupled. In a six resonator filter, the second and fifth resonators are cross-coupled.
Claims12
A low loss surface acoustic wave filter comprising a circuit formed of a thin film of metallization on a substrate, said circuit having at least four resonators sequentially arranged on said substrate, said circuit having an input and an output with cross coupling means to cross couple two of said resonators, said resonators resonating in at least one mode.
A method of operating a low loss acoustic wave filter comprising a circuit formed of a thin film of metallization on a substrate, said substrate being located in a housing, said circuit having at least four resonators sequentially arranged on said substrate, said circuit having an input and an output with cross coupling means to cross couple two of said resonators, said method comprising operating said filter to cross couple two non-sequential resonators.
Dependencies are inferred from the claim text.