Patent ID: 7176776
Filing Date: 2007-02-13
Classification: H01F,H01P,H03H,H05K

Abstract:
1. A filter-balun combination for filtering an input signal provided to the filter-balun combination and providing a balanced output signal from the filter-balun combination, comprising: a multi-layer planar substrate including multiple planar dielectric layers, multiple planar device layers comprising conducting material, and multiple conducting structures electrically coupling conducting material in different device layers through at least one dielectric layer; a filter comprising a first inductor and a second inductor, the first inductor comprising electrically conducting traces formed in at least one of said multiple planar device layers, said first inductor having an input, an output, and at least one turn, the second inductor comprising electrically conducting traces formed in at least one of said multiple planar device layers, said second inductor being symmetrical to said first inductor about a plane that is equidistant from said first and second inductors and perpendicular to the surface of said multi-layer planar substrate, said second inductor having an input coupled to the output of said first inductor, said second inductor further having an output; and a balun comprising a first electrically conducting central transmission line coupled to the output of said second inductor and forming in one of said multiple device layers a first path that includes first and second coil areas, said balun further comprising first and second output structures, each of which includes upper and lower electrically conducting transmission lines having first and second ends, the transmission lines forming substantially overlapping paths in planar device layers located above and below the device layer of said first electrically conducting central transmission line, wherein the substantially overlapping paths of said upper and lower electrically conducting transmission lines of the first output structure substantially overlap the first path of said first electrically conducting transmission line in the first coil area, and wherein the substantially overlapping paths of said upper and lower electrically conducting transmission lines of the second output structure substantially overlap the first path of said first electrically conducting central transmission line in the second coil area, and wherein the upper electrically conducting transmission line and lower electrically conducting transmission line of each of the first and second output structures are electrically coupled near where the electrically conducting transmission lines terminate and provide a signal output at the first ends of the transmission lines.