In this paper, a wafer-level System-in-Packaging structure using through silicon via (TSV) for integration on both sides of the silicon wafer is presented. It is composed of BCB/ metal multilayers, high-resistivity silicon substrate with TSV. To reduce the transmission loss in microwave frequency, not only the high-resistivity silicon is used, but also a special TSV structure with 6 grounded shielding vias around the core via are adopted. Microstrip line (MSL) is used to transmit high-frequency signal on package plane together with the low permittivity intermediate dielectric polymer, BCB. Descriptions on the interconnection structure and the fabrication process are included. The microwave measurement result of the MSL connected by TSVs is measured up to 35GHz. The results of both the simulation and the measurement are presented.