Abstract: A lamp capable of emitting electromagnetic radiation (9), for example visible, IR or UV radiation, exploiting the activation of substances (4) triggered with an antenna (6) irradiating microwaves (8) located inside and insulated, in focal position. Advantageously, the substances (4) are put into a chamber (3) obtained by introduction of a first bulb (1) in a second bulb, in order to form the chamber (3) closed between the walls of the first (1) and of the second bulb (2), the walls of the first bulb defining the recess (5) which houses the antenna (6). A better energy efficiency and a better economy is obtained with respect to the conventional techniques which require introduction of the lamp in a metal vessel crossed by microwaves, or under external microwaves beams. It belongs to the category of lamps without electrodes, because the atoms or the other particles that emit the radiation (8) are neither in contact with the antenna nor with other metal parts.