Electromagnetic and Particle-in-Cell Simulation Studies of a High Power Strap and Vane CW Magnetron

Abstract

This paper presents electromagnetic and particlein-cell (PIC) simulation studies of ring strapped vane resonator of a 2.45 GHz 1-kW magnetron using Computer Simulation technology microwave studio and MAGIC-3-D. The aim was to gain design understanding through the analysis of constituent parts of the resonant system and to deduce results having significant engineering value. The electromagnetic analysis includes modeling the effect of the end-gap length, the straps, the coupling antenna, and the surface roughness of cavity wall on resonant frequency. It was found that a clearance of 4 mm and beyond between cavity resonator and end plate have negligible effect on resonance frequency. Straps influence the resonant frequency of the π mode maximum, and can be used to control and fine tune the resonant frequency of the desired π mode. A surface roughness of 1 μm or more affects the unloaded Q of the resonator cavity adversely. Coupling antenna height is found to play an important role to achieve desired Q l and Q ext for the segment loaded axial extraction of power. The PIC simulation study predicted that the hot resonant frequency differ from cold resonant frequency by ∼9 MHz. The computed frequency, power, and efficiency were found to be 2.462 GHz, 1.3 kW, and 70%, respectively.Index Terms-Cold resonant frequency, electromagnetic and particle-in-cell (PIC) simulation, hot resonant frequency, industrial magnetron, virtual prototyping.

Strapped Magnetron Performance Affected by Dielectric Material Filling

“…In the cold test setup, the magnetron is connected to the vector network analyzer port by a coaxial transition. The value of voltage standing wave ratio of coaxial taper transition is less than 1.1 in the frequency range of interest [10]. The measured frequencies of π-mode and next higher mode are 2.445 and 3.735 GHz, respectively, as shown in Fig.…”

“…The particle in cell (PIC) simulation helps to simulate the output performance of magnetron by simulating the interaction behavior of the RF circuit with the electron beam [10]. The operating point for the π-mode of oscillation in the magnetron was obtained from the Hull cutoff voltage (V c ) and the Buneman-Hartree voltages (V T ) plots as a function of the external magnetic field (B).…”

Synthesis and Simulation Studies of a 10-kW 2.45-GHz CW Magnetron

“…In the next step the major parameters of the resonant system of a 1-kW 2.45-GHz CW magnetron have been normalized using the operating π-mode wavelength as given in the following equations [1]:…”

“…The large mismatch in Q values may be due to the inferior surface finish of the cavity walls and it is expected that this will improve with better surface finish [1]. …”

“…This approach provides flexibility in the design of industrial microwave generators and ovens. Electromagnetic, particle-in-cell (PIC), and thermal studies of theses magnetrons have gathered pace after the availability of powerful computer codes [1]- [7]. The design time depends on the accuracy of initial dimensions.…”