Microwave oven with rotating tray

A microwave oven, which comprises:

• a chamber having a bottom wall;
• a single, horizontal rotating tray located in said chamber for receiving thereon items subjected to microwaving operation, wherein said tray is rotatable about a concentric axis thereof during the operation and puts said items into motion along a non-circular path forming a three-dimensional curve in space;
• and
• a mechanism connected to said tray for moving said tray about said concentric axis along said non-circular path while continuously maintaining said tray horizontal wherein said horizontal tray is circular and is provided, on a rim portion of a circular lower surface thereof, with at least three castor wheels with substantially horizontal axes of rotation, angularly spaced and aligned on a substantially circular line, and wherein, on said bottom wall of said chamber, a circular running track is located for the castor wheels, said track being positioned concentric to the vertical axis of rotation of said tray and having a diameter equal to that of a circular line of alignment of said castor wheels, said track also being formed by an alternating succession of angularly spaced bosses and hollows, said number of bosses and hollows being at least the same as the number of castor wheels of the horizontal tray.