The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 28, 2009
Filed:
Sep. 24, 2007
Toshiyuki Abe, Tokyo, JP;
Tatsuya Fukunaga, Tokyo, JP;
Toshiyuki Abe, Tokyo, JP;
Tatsuya Fukunaga, Tokyo, JP;
TDK Corporation, Tokyo, JP;
Abstract
A stacked filter includes an array of resonant sections, the resonant sections adjacent each other being electromagnetically coupled, a first resonator electromagnetically coupled to the resonant section on one end of the array of the resonant sections, and a second resonator electromagnetically coupled to the resonant section on the other end thereof. Each of the resonant sections has a pair of interdigital coupled quarter-wave resonators, and a passing frequency as a filter is set to a value flower than a frequency fdetermined by a physical length λ/4 of the quarter-wave resonator. The first and second resonators have a physical length of λ/4, where λis a wavelength corresponding to the passing frequency f. The stacked filter enables miniaturization and sufficient impedance matching with external circuits in a broad band, resulting in excellent filter characteristics in the broad band.