Abstract: An electrodeless microwave-generated radiation apparatus includes a microwave cavity wall made of metal material defining a microwave cavity, a lamp arranged in the microwave cavity containing emission material, a microwave generator supplying microwaves for exciting the emission material in the lamp, a microwave-coupling means coupling microwaves to the lamp through a waveguide, and a dielectric mirror arranged behind the lamp. The rise time of the apparatus can be remarkably shortened compared with the known art so that the damage of a magnetron can be reduced. The intensity of emission along the lamp is controlled by a projection or parasitic element. Further, by the use of a dielectric mirror, the object can be processed without temperature of the object to rise too high.