Patent ID: 6523252
Filing Date: 2003-02-25
Classification: H01P,H05K,Y10T

Abstract:
A method for forming a multi-layer circuit board having a coaxial conductor embedded therein, the multi-layer circuit board comprising at least a first board layer with a lower surface and an upper surface, and at least a second board layer with a lower surface and an upper surface, and at least a second board layer with a lower surface and an upper surface, said coaxial conductor comprising an inner conductor, an outer conductor enclosing the inner conductor at least partly, and a dielectric placed between said inner conductor and outer conductor, said method comprising the steps of:separately depositing a first via and a second via into corresponding grooves of the first board layer, the second via being disposed at a distance from the first via, the first and second vias forming part of said outer conductor, and said first board layer forms part of said dielectric between said first and second vias; separately depositing a third via and a fourth via into corresponding grooves of the second board layer, the fourth via being disposed at a distance from the third via, the third and fourth vias forming part of said outer conductor, and said second board layer forms part of said dielectric between said third and fourth vias; embedding a first strip conductor on the lower surface of said first board layer, between said first and second vias, or on the upper surface of said second board layer, between said third and fourth vias, to form said inner conductor, embedding a second strip conductor on the upper surface of said first board layer, to form part of sail outer conductor, wherein an electric coupling is formed by means of said second strip conductor between said first and second vias, embedding a third strip conductor on the lower surface of said second board layer, to form part of said outer conductor, wherein an electric coupling is formed by means of said third strip conductor between said third and fourth vias, and stacking said separate first and second board layers together in a way that said first via and third via have and electric contact to each other, that said second via and fourth via have an electric contact to each other, and that said first strip conductor is left between said first and second board layers.