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:
Aug. 24, 1993
Filed:
Mar. 31, 1992
Applicant:
Inventors:
Aimo Turunen, Oulu, FI;
Pauli Nappa, Oulu, FI;
Assignee:
Lk-Products Oy, Kempele, FI;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01P / ; H04B / ;
U.S. Cl.
CPC ...
333134 ; 333206 ; 455 82 ;
Abstract
Previously it was not possible to realize a ceramic duplex filter using a single monolithic ceramic block, because the isolation between the transmitter branch and the receiver branch could not be made sufficiently high. A duplex filter (1) can be realized in a single ceramic block by making, between its filters (A and B), a strip-like area (9) on the non-coated surface (5) of the ceramic block, due to which the electric and magnetic coupling between the resonators (R.sub.4, T.sub.1) of filters (A and B) on each side of the area can be adjusted to almost zero. This 'electric partition' (9) provides a sufficient isolation between the filters of each branch.