the output of the microwave oven at a constant level regardless of the load of the food the microwaves are divided into a plurality of wave streams and the wave streams are made to have different phases the microwave oven includes an input wave guiding tube coupled with a magnetron for receiving microwaves from the magnetron a first output wave guiding tube communicates to the input wave guiding tube for receiving the microwaves from the input wave guiding tube to diffusely irradiate the microwaves into a cavity a second wave guiding tube communicates to the input wave guiding tube for converting the microwaves to a phase different from that of the first wave guiding tube to irradiate them into the cavity application_number US 92328897 A description fig5 is a schematic view showing a first embodiment of the wave guiding tube of the microwave oven according to the present invention the wave guiding tube of fig5 is a top feeding type tube in which microwaves are irradiated from the top into the cavity as shown in fig5 the wave guiding tube of the first embodiment includes an input wave guiding tube 21 a first output wave guiding tube 23 and a second output wave guiding tube 25 the first and second output wave guiding tubes 23 and 25 are separated from each other by an intermediate stub 27 the first and second output wave guiding tubes 23 and 25 respectively include a plurality of openings 29 through which the microwaves are irradiated into the cavity the input wave guiding tube 21 is coupled to a magnetron not shown in the drawings for supplying.