The present invention relates to a device for receiving and/or transmitting electromagnetic waves with radiation diversity. This device comprises, on a common substrate, at least one antenna of the slot type formed by a closed curve, known as a slot antenna, electromagnetically coupled to a first supply line, and an antenna radiating parallel to the substrate, positioned inside the slot antenna and connected to a second supply line, said first and second supply lines being connected via a switching means to means for exploiting the electromagnetic waves. The device can be applied, in particular, in the field of wireless transmissions.