Microwave oven with phase modulator and fan on common driveshaft

A microwave oven comprising a magnetron for delivering microwave power to a cavity of the oven, a rotatable phase modulator for preventing the establishment of dominant standing waves in the cavity, and a forced hot air system comprising an electrical resistance heater and a rotatable fan for forcing air over the heater and through the cavity, wherein the phase modulator and the fan are mounted on a common driveshaft which extends through a launch box by means of which microwave power is delivered from the magnetron to the cavity, wherein the phase modular has blades extending from one or both sides of a disc-like plate disposed in a plane perpendicular to the rotational axis of the shaft, and wherein the disc-like plate is spaced from the internal surface of the outer wall of the launch box by a distance corresponding to a quarter wavelength at the operating frequency of the magnetron and wherein the fan also has blades extending from one or both sides of a disc-like plate disposed in a plane perpendicular to the rotational axis of the shaft, and wherein the respective planes of the disc-like plates of the modulator and the fan are spaced by distance corresponding to a quarter wavelength, the fan being further away from an outer wall of the launch box than the phase modulator.

A microwave oven comprising a magnetron for delivering microwave power to a cavity of the oven, a rotatable phase modulator for preventing the establishment of dominant standing waves in the cavity, and a forced hot air system comprising an electrical resistance heater and a rotatable fan for forcing air over the heater and through the cavity, wherein the phase modulator and the fan are mounted on a common driveshaft, wherein a metal plate is fixed in the cavity and serves not only as a match plate for transferring microwave power to the cavity bit also serves as a baffle plate for the forced hot air convection system, and wherein the metal plate is supported in the cavity so that a front surface of the metal plate faces into the cavity and a rear surface of the metal plate faces a launch area, there being a spacing between the peripheral edge of the metal plate and the walls of the cavity, the spacing being defined partly by an air gap and partly by blanking material which allows the passage of microwave power but blocks or impedes the passage of forced hot air.