An interposer element in a multidimensional integrated circuit with stacked elements has one or more conductors, especially power supply lines, coupled through decoupling networks defining low impedance shunts for high frequency signals to ground. The interposer has successive tiers including silicon, metal and dielectric deposition layers. The decoupling network for a conductor has at least one and preferably two reactive transmission lines. A transmission line has an inductor in series with the conductor and parallel capacitances at the inductor terminals. The inductors are formed by traces in spaced metal deposition layers forming coil windings and through vias connecting between layers to permit conductor crossovers. The capacitances are formed by MOScaps in the interposer layers. An embodiment has serially coupled coils with capacitances at the input, output and junction between the coils, wherein the coils are magnetically coupled to form a transformer.