Advanced internet and multimedia set-top boxes are today massively based on 4*4 MIMO systems, with multi-sub-bands standards (WIFI bands, LTE, Bluetooth,…). Interconnections between the numerous access ports of different radio chipsets mounted on a main PCB (Printed Circuit Board) and multiple antennas spatially distributed on the plastic casing become therefore a great challenge for cost and performances motivations. The flex technology, based on well-controlled and low cost process, brings new functionalities and opportunities for assembling subsystems , under compactness considerations, as well as electrical performances improvement. In this paper, we discuss about the characterisation of connectors used for flexible printed circuit to a main PCB interconnections. The choice of the connectors is a critical issue, and must be properly done considering both local ground and signal interconnections constraints. Simulation and measurements are performed up to 15Ghz covering WIFI bands.