Surface wave device balun resonator filters
CA 2233835 C · Owner: Bell-Northern Research Ltd. · Inventors: Xu, Yufeng; Dai, Ji-Dong; Cameron, Thomas Philip
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A surface wave device comprises first and second SPUDT (single phase unidirectional transducer) resonator filters (72 74) each comprising first and second, transducers which are preferably RSPUDTs (resonant SPUDTs) the resonator filters, being the same except that one transducer (R1M) of the second resonator filter is a mirror image of the corresponding transducer (R1) of the first resonator filter to provide a phase difference of 180°. The surface wave device serves as a balun by having an unbalanced signal connection (78) to the first transducers and a balanced signal connection (84, 84') comprising signal connections to the second transducer of each of the first and second resonator …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed April 1, 1998 and granted August 1, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 1, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 1, 2020.
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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.