Song Yue

Theoretical Investigation and Simulation of Resonant System of Sector and Hole-and-Slot Resonator Type Rising-Sun Magnetron

In this paper, a sector-step approximation (SSA) model is introduced. With step admittance recurrence and field matching relation, the dispersion equation of rising-sun magnetron (RSM) with arbitrary resonators is derived. By this model, resonant frequencies of a 10-resonator sector and hole-and-slot resonator type RSM (SHSRSM) are theoretically calculated. In addition, computer simulation is performed to verify the accuracy of the theory. Besides, the effects of the hole radius on magnetrons main characteristic parameters are analyzed, such as π-mode resonant frequency, mode separation, and quality factor. The optimized SHSRSM is compared with two common kinds of RSMs, such as sector resonator type RSM (SRSM) and sector-and-slot resonator type RSM (SSRSM). The results show that the theoretical results are well consistent with the simulation results, and the maximum relative error is less than 3%, which verifies the accuracy and feasibility of the SSA model. Compared with SRSM and SSRSM, SHSRSM has greater mode separation and quality factor, which improves the stability and the energy storage of RSM.

Equivalent Circuit Method of Resonant System of Magnetron With Sector-and-Slot Resonant Cavities

In this paper, the equivalent capacitance and inductance of sector-and-slot resonant cavities are investigated theoretically by the equivalent circuit method. Thereby, the expression of the resonance frequency is obtained as a function of structure dimensions. In addition, the effects of structure dimensions on equivalent capacitance, inductance, and π-mode frequency are analyzed numerically, especially the slot width, slot length, and height. The results show that, compared with field theory, the equivalent circuit method is in more consistent with the simulation results, which verifies the validity of the equivalent circuit method. With the given structure dimensions, the equivalent capacitance increases with the increasing of slot length and height or the decreasing of slot width, while the equivalent inductance is opposite. Therefore, the change tendency of resonance frequency is determined by the relative changes of the capacitance, inductance, and coupling capacitance. This method can help to predesign and analyze resonant system of magnetrons with sector-and-slot resonant cavities efficiently.

Simulation and experiment measurement of High power continuous wave magnetron

In this paper, a six-cavity High power continuous wave magnetron (HPCWM) is built by MAGIC Code. The power and frequency of the HPCWM with different anode voltages and magnetic field are obtained. A corresponding HPCWM, which is operated with different magnetic field, is performed experiment measurement. Both the simulation and experiment results are compared with each other, which is very helpful to promote the research and application of HPCWM.

3D particle-in-cell simulation of continuous wave magnetron

In this paper, a 2.45GHz 12-resonator high-power continuous wave magnetron is simulated to investigate the influence of voltage, magnetic field and electric current on the power and efficiency of the magnetron. The beam emission model and input waveguide port excitation are adopted. Voltage and magnetic field operating range in simulation are relative narrow. The Power approximately increases linearly with the increase of anode current, and the magnetron has high energy conversion efficiency. With the increase of cathode current, anode current increases quickly at first, then decreases slowly and reaches stable stage in the end.

Theoretical investigation of frequency characteristics of free oscillation and injection-locked magnetrons*

The frequency characteristics of free oscillation magnetron (FOM) and injection-locked magnetron (ILM) are theoretically investigated. By using the equal power voltage obtained from the experiment data, expressions of the frequency and radio frequency (RF) voltage of FOM and ILM, as well as the locking bandwidth, on the anode voltage and magnetic field are derived. With the increase of the anode voltage and the decrease of the magnetic field, the power and its growth rate increase, while the frequency increases and its growth rate decreases. The theoretical frequency and power of FOM agree with the particle-in-cell (PIC) simulation results. Besides, the theoretical trends of the power and frequency with the anode voltage and magnetic field are consistent with the experimental results, which verifies the accuracy of the theory. The theory provides a novel calculation method of frequency characteristics. It can approximately analyze the power and frequency of both FOM and ILM, which promotes the industrial applications of magnetron and microwave energy.

Theoretical analysis and simulation of resonant system of high power continuous wave magnetron

Resonant frequencies of a 12-cavity magnetron with sector-and-slot cavities are calculated by both simulation and field theory derived by sector-step approximation method. Besides, the effects of main structure dimension of sector-and-slot cavity on π-mode resonant frequency and mode separation are analyzed by the given field theory. Results show that the theory results are consistent well with simulation results and the relative error is less than 1%. Π-mode resonant frequency increases with the increasing of slot length and slot width. In addition, mode separation increases with the increasing of slot width. And with the increasing of slot length, the mode separation decreases at first and then goes to stable state.

3D particle-in-cell simulation of S band high power continuous wave magnetron

Magnetrons have been proved to be one of the most efficient and economical industrial microwave generators, which are widely used in microwave drying, microwave pasteurization, and so on. Unfortunately, there is little paper concerning about 3D simulation of CW magnetron although its production increases significantly. In this paper, 3D particle in cell simulation of an S band 30 kW CW magnetron has been addressed in details by CST particle studio. In this model, anode voltage is 12.1 kV, anode current is 3.1 A, focusing magnetic field is 1650 Gs, operating frequency is 2450 MHz. 12 sector-slot cavities with double strapped rings are introduced to achieve high efficiency and high power in CW operating condition. Simulation results show that spoke-like electron cloud appears obviously and output power of magnetron is 30kW while efficiency is nearly 80%.

Theoretical investigation of resonant frequencies of unstrapped magnetron with arbitrary side resonators

In this paper, a sector steps approximation method is proposed to investigate the resonant frequencies of magnetrons with arbitrary side resonators. The arbitrary side resonator is substituted with a series of sector steps, in which the spatial harmonics of electromagnetic field are also considered. By using the method of admittance matching between adjacent steps, as well as field continuity conditions between side resonators and interaction regions, the dispersion equation of magnetron with arbitrary side resonators is derived. Resonant frequencies of magnetrons with five common kinds of side resonators are calculated with sector steps approximation method and computer simulation softwares, in which the results have a good agreement. The relative error is less than 2%, which verifies the validity of sector steps approximation method.

Three dimension PIC simulations of A 2.45GHz injection-locked magnetron with sector-and-slot-type resonators

A 12-cavity magnetron with sector-and-slot-type resonators is simulated by PIC code to obtain its output frequency and output power. A new three symmetric gaps injection model is adopted to inject signal into the magnetron. Then PIC simulation of this injection-locked magnetron is accomplished successfully and the output frequency of injection-locked magnetron is drawn from.