As a novel vircator device, the coaxial vircator can attain much higher efficiency than the common virtual cathode oscillator. In this paper, coaxial vircators in three specific configurations are studied to describe ...As a novel vircator device, the coaxial vircator can attain much higher efficiency than the common virtual cathode oscillator. In this paper, coaxial vircators in three specific configurations are studied to describe the efficiency and frequency characteristics and their dependence on geometric parameters. The PIC (Particle in Cell) simulation results show that a power efficiency over 11% can be obtained from the coaxial vircator with a finite inner anode conductor, and a narrow-band output can be achieved. A direct-coupled coaxial vircator has a slightly lower efficiency of about 8%, but in this configuration the efficiency is not strongly dependent on the geometry parameters. The introduction of a reflecting cavity can effectively improve the efficiency under certain parameters. Meanwhile, the research results also indicate that improper cavity parameters will countervail some inherent advantages of the configuration with a finite inner conductor, leading to lower efficiency than that of the direct-coupled one. Meanwhile, an experiment was also carried out to testify the simulation results, and a power efficiency over 3% was obtained from the direct-coupled coaxial vircator.展开更多
An axially extracted virtual cathode oscillator (vircator) with a feedback annulus is proposed and configured through particle-in-cell (PIC) simulation in Ref. [1]. In this paper, the effects of the feedback mechanism...An axially extracted virtual cathode oscillator (vircator) with a feedback annulus is proposed and configured through particle-in-cell (PIC) simulation in Ref. [1]. In this paper, the effects of the feedback mechanism are studied through PIC method. The simulated results indicate that the improved new vircator can increase the output power twice large than that of the axially-extracted conventional vircator under the same condition. On the other hand, it can narrow the bandwidth and purify the modes.展开更多
基金The project supported by the National 863 Project of China (No. 2002AA834060)
文摘As a novel vircator device, the coaxial vircator can attain much higher efficiency than the common virtual cathode oscillator. In this paper, coaxial vircators in three specific configurations are studied to describe the efficiency and frequency characteristics and their dependence on geometric parameters. The PIC (Particle in Cell) simulation results show that a power efficiency over 11% can be obtained from the coaxial vircator with a finite inner anode conductor, and a narrow-band output can be achieved. A direct-coupled coaxial vircator has a slightly lower efficiency of about 8%, but in this configuration the efficiency is not strongly dependent on the geometry parameters. The introduction of a reflecting cavity can effectively improve the efficiency under certain parameters. Meanwhile, the research results also indicate that improper cavity parameters will countervail some inherent advantages of the configuration with a finite inner conductor, leading to lower efficiency than that of the direct-coupled one. Meanwhile, an experiment was also carried out to testify the simulation results, and a power efficiency over 3% was obtained from the direct-coupled coaxial vircator.
基金The project supported by the National 863 Project of China (No. 2002AA834020)
文摘An axially extracted virtual cathode oscillator (vircator) with a feedback annulus is proposed and configured through particle-in-cell (PIC) simulation in Ref. [1]. In this paper, the effects of the feedback mechanism are studied through PIC method. The simulated results indicate that the improved new vircator can increase the output power twice large than that of the axially-extracted conventional vircator under the same condition. On the other hand, it can narrow the bandwidth and purify the modes.
