High Power Magnetron
Abstract:The EMPro Eigenmode solver is used to analyze a high power Magnetron.Cavity magnetrons are commonly used in radar systems, microwave ovens and other applications. In this example, the magnetron is constructed of two concentric cylinders. The output cylinder has corrugations in its inner wall (these corrugations some times is called Vanes). The central cylinder is perfect conductor rod. The cylindrical cavity has 8-slot corrugated walls.
Figure 1: Cavity magnetron example
The cavity magnetron is a high-powered vacuum tube that generates microwaves using the interaction of a stream of electrons with a magnetic field. The sizes of the cavities determine the resonant frequency, and thereby the frequency of emitted microwaves. It’s a challenging task to know and precisely control resonant frequencies . Eigenmode simulation is required to know all the frequencies for different modes.
The EMPro Eigenmode solver can be used to analyze closed resonant structures such as this magnetron example. EMPro includes a full 3D modeling environment that allows the creation or import of 3D structures.
Figure 2: 3D model of magnetron in EMPro
Figure 3: Eigenmode Simulation setup in EMPro
Primary results are, besides the field distribution of the modes, the Eigen frequencies of the structure and Q values. Typical application areas are the determination of the poles of a highly resonant filter structure, Q-value calculation, and the design of accelerating cavities like Magnetrons. Using eigenmode simulation, resonant frequencies and Q values have been analyzed for first 20 modes.
Figure 4: Eigenmode analysis results, showing resonant frequencies and Q values
Figure 5: Field plots for four of the resonant frequencies
Designers can quickly design and tune magnetron design parameters to get desired resonance frequencies using the Eigenmode solver in EMPro.