A wireless handheld or portable device comprising: a radiating system configured to transmit and receive electromagnetic wave signals in a first frequency region and included within the wireless handheld or portable device; the radiating system comprising a radiating structure, a radiofrequency system and an external port; the radiating structure comprising a ground plane layer including a connection point, a radiation booster including a connection point and an internal port; the internal port is defined between the connection point of the radiation booster and the connection point of the ground plane layer; the radiofrequency system comprising a first port connected to the internal port of the radiating structure and a second port connected to the external port of the radiating system; the input impedance of the radiating structure at the internal port when disconnected from the radiofrequency system has an imaginary part not equal to zero for any frequency of the first frequency region; and the radiofrequency system is configured to provide impedance matching to the radiating system in the first frequency region; characterized in that the radiation booster has a maximum size smaller than 1/20 times a free-space wavelength corresponding to a lowest frequency of the first frequency region; the radiation booster comprises two conductive elements (201, 202) and a dielectric element having a parallelepiped shape; the two conductive elements (201, 202) are connected by at least one via hole through the dielectric element; the connection point of the radiation booster is a point defined in a conductive element of the two conductive elements. a radiating system configured to transmit and receive electromagnetic wave signals in a first frequency region and included within the wireless handheld or portable device; the radiating system comprising a radiating structure, a radiofrequency system and an external port; the radiating structure comprising a ground plane layer including a connection point, a radiation booster including a connection point and an internal port; the internal port is defined between the connection point of the radiation booster and the connection point of the ground plane layer; the radiofrequency system comprising a first port connected to the internal port of the radiating structure and a second port connected to the external port of the radiating system; the input impedance of the radiating structure at the internal port when disconnected from the radiofrequency system has an imaginary part not equal to zero for any frequency of the first frequency region; and the radiofrequency system is configured to provide impedance matching to the radiating system in the first frequency region; characterized in that the radiation booster has a maximum size smaller than 1/20 times a free-space wavelength corresponding to a lowest frequency of the first frequency region; the radiation booster comprises two conductive elements (201, 202) and a dielectric element having a parallelepiped shape; the two conductive elements (201, 202) are connected by at least one via hole through the dielectric element; the connection point of the radiation booster is a point defined in a conductive element of the two conductive elements.