Abstract: A testing apparatus includes a tester and a probe card system that includes a probe card connected to the tester, and an active interposer connected to the probe card and wirelessly coupled with a device to be tested. The active interposer includes pads positioned on its free surface facing the device. The pads are positioned with respect to pads of the device so that each pad of the active interposer faces a pad of the device and is separated therefrom by a dielectric. Each pair of facing pads forms an elementary wireless coupling element which allows a wireless transmission between the active interposer and the device. The active interposer also includes an amplifier circuit configured to amplify wireless signals from the device before forwarding them to the tester. The probe card system includes a transmission element able to transmit a power voltage from the tester to the device.