Design of ISM-Band High Power and High Efficiency Solid-State VCOs for Use in Next Generation Microwave Oven

Recently, intelligent heating, next generation microwave ovens that achieve uniform heating and spot heating using solid-state devices, has been actively studied. There are two types of microwave generators using solid-state devices. Since compactness is indispensable to accommodate in a limited space, the miniaturized oscillator type was selected. The authors proposed an imbalanced coupling resonator, a resonator-less feedback circuit, a high power frequency variable resonator, and injection-locked phase control in order to achieve high performance of the oscillator type microwave generator. In addition, we confirmed that the oscillator type can be used as the microwave generator for intelligent heating using a Wilkinson combiner. As a result, it was demonstrated that the oscillator type microwave generator, realized the same high efficiency (67%) as the amplifier type, and found the possibility of variable frequency (2.4 to 2.5GHz) and variable phase, and can be used as the microwave generator for intelligent heating.