Oscillation mechanism of avalanche region of the IMPATT diode

The oscillation mechanism of the avalanching region of the IMPATT diode is clarified by referring to the cavity resonator and feedback theories. When the avalanche takes place, the microwave electric field and the particle currents grow spacially. But the spacial growth does not directly mean the self-oscillation, as there exists the reflection loss at the region edges. When the gain due to the avalanche exceeds the reflection loss, the self-oscillation can take place. The preceding phenomena are analyzed by the conception of the open-loop transfer gain in feedback theory.