| 摘要 |
The present invention proposes a coupling device, comprising a substrate ( 1 ), a conductive layer ( 2 ) covering a first surface of said substrate ( 1 ), at least two electromagnetically coupled lines ( 3 a, 3 b) being provided opposite to said first surface and at least one thereof being covered by at least one cover layer ( 4, 5 ) wherein at least one capacitor (C 1, C 2, C 3, C 4 ) is connected between a first end of at least one of said at least two lines ( 3 a, 3 b) and said conductive layer ( 2 ). The at least one capacitor is a buried capacitor grounded in order to equalize unequal phase velocities otherwise degrading the performance of e.g. broadside coupled structures in an inhomogeneous substrate structure such as for example microstrips in a multilayer LTCC. Therefore the present invention enables coupling devices having a high performance and offering in that way the best of all possible design scenarios in terms of wideband performance, size and cost. |
