We evaluated low-impedance power distribution network (PDN) of decoupling capacitor embedded interposers for 3-D integrated LSI system. Measurements are carried out using the developed impedance analyzer system of a wide frequency range for evaluating ultralow impedance, and calculations are carried out using 2.5-D finite element method (FEM) electromagnetic field simulator. We fabricated various types of capacitor mounted or capacitor embedded interposers test element group (TEG), such as surfacemounted and embedded chip capacitors, and thin film capacitors on silicon interposers using the same simple design to compare measurement results with calculation ones. As a result, the chip capacitor embedded organic interposer TEG and thin film capacitor embedded silicon interposer TEG could provide low PDN impedance at a wide frequency range of up to 40 GHz. In particular, the interposer TEGs of the thin film capacitor embedded interposer that shows a low impedance of 0.1Ωcould be evaluated and calculated accurately. By using chip capacitor embedded or thin film capacitor embedded interposers for 3-D integrated LSI system, it is expected that the PDN of the system can be achieved ultralow PDN impedance.