Development of A W-band High-power Spatial Harmonic Magnetron

It is well known that the magnetron is a kind of high-power vacuum devices but it could not effectively operate at high frequency above 90 GHz. It is an effective method to synchronize with spatial harmonic at high frequency. A W-band spatial harmonic magnetron which its electron interacts with the first backward harmonic of the radio-frequency field of $\pi$ mode or its adjacent mode is presented. This kind magnetron has the advantages of large-power, high-efficiency and miniaturization. The simulation analysis, cold characteristic test and hot test experiment are detailedly introduced. The test data showed the device was able to deliver an output power of $\sim 10.0$ kW and an efficiency of $\sim 8$ % with a pulse width of 420ns and a duty factor of 0.1 %.

I. Introduction

It is well known that the magnetron is a kind of high-power vacuum devices. But it could not effectively operate at frequency above 90 GHz, because of that: 1) The dimensions of magnetron cavity become too small to manufacture since they scale as wavelength. 2) The DC magnetic field is too high to realize miniature because it is inversely proportional to the wavelength. ^[1]