(a) Photo of the shield and the filters. The shield is coated with the IR absorbing material (black color). The filters are mounted on the shield and the cracks are sealed by the IR absorbing material. In our design, 12 filters are combined: half of them are impedance matched (silver color) and the other half are not (golden color). (Insert) Zoomin of the IR filter which is not filled with Stycast 2850FT. From the inject hole, the soldered pins are clearly seen. (b) Schematic representation of the sample stage. The 3D transmon is mounted inside the shield on the copper block (black color) for heat sinking and the microwave lines are connected through the filters. The shield is mounted on the 20 mK mixing chamber stage of a dilution refrigerator.