Abstract: Conventional stripline implementations of couplers in Multilayer Ceramic Integrated Circuit (MCIC) technology incur a cost disadvantage when compared to an equivalent microstrip implementation. This is primarily due to the increased substrate thickness needed to achieve the required performance. Conventional stripline couplers significantly limit our ability to optimise for smaller substrate thickness and therefore overall cost. However, stripline couplers are needed for stacked integration scenarios and as building blocks for complex active and passive RF circuits in MCICs. A method of implementation that overcomes this practical disadvantages is therefore highly desirable. To this end, the present invention presents a novel coupling device structure that enable RF designers to use the stripline coupler configuration, by achieving required levels of performance with much reduced substrate thickness.

Abstract: 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 (3a, 3b) 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 (C1, C2, C3, C4) is connected between a first end of at least one of said at least two lines (3a, 3b) 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.

Abstract: Conventional stripline implementations of couplers in Multilayer Ceramic Integrated Circuit (MCIC) technology incur a cost disadvantage when compared to an equivalent microstrip implementation. This is primarily due to the increased substrate thickness needed to achieve the required performance. Conventional stripline couplers significantly limit our ability to optimise for smaller substrate thickness and therefore overall cost. However, stripline couplers are needed for stacked integration c scenarios and as building blocks for complex active and passive RF circuits in MCICs. A method of implementation. that overcomes this practical disadvantages is therefore highly desirable. To this end, the present invention presents a novel coupling device structure that enable RF designers to use the stripline coupler configuration, by achieving required levels of performance with much reduced substrate thickness.

Abstract: A conductive structure having a conductor for carrying a signal at a one or more operating frequencies of the structure, the conductor comprising: at least two electrically conductive strips spaced apart by a dielectric and arranged in parallel to extend from a first node to a second node, the conductive strips being interconnected between the nodes by at least one inter-strip electrically conductive connection through the dielectric; the maximum physical dimension of the or each inter-strip connection and the maximum physical separation of potentially successive inter-strip connections being equal to or less than one quarter of the free space wavelength corresponding to the minimum operating frequency of the structure.

Abstract: 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 (3a, 3b) 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 (C1, C2, C3, C4) is connected between a first end of at least one of said at least two lines (3a, 3b) 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.