Jiayin Li

Studies of the Frequency-Agile Relativistic Magnetron

A frequency-agile relativistic magnetron in S-band is studied in the theory and experiment. The effects of zero-order component and frequency separation are analyzed in the different resonated structures. It shows that the zero-order component is a main obstacle in the higher frequency section in contrast to the frequency separation in the lower frequency section. The experimental research is carried out to verify the theoretical results. The 500-MHz bandwidth is attained under the power of about 1 GW in the experiments of frequency-agile relativistic magnetron.

Experimental Studies on the A6 Relativistic Magnetron With Permanent Magnet

This paper presents the results of the experimental investigation of an A6 relativistic magnetron (RM) with permanent magnet. A series of permanent magnets was fabricated. The maximum axial magnetic field Bz is 5.9 kGs. The 540-MW peak output power with a pulsewidth up to 40 ns of the RM with permanent magnet is obtained at the operation frequency of 2.65 GHz.

Numerical Analysis of a Ka-Band Third-Harmonic Magnetron-Type Slotted Peniotron

In this paper, we have numerically investigated the operating characteristics of a ka-band magnetron-type slotted peniotron. The third-harmonic four-vane peniotron operates in a circularly polarized 2π mode. The MAGIC3D simulation shows that, with proper acceleration voltage, beam current, and axis-encircling electron beam, the peniotron is predicted to generate a pure 2π-mode electromagnetic wave with output power of 45 kW at 29.7 GHz and conversion efficiency of up to 66.7%. Critical characteristics such as the start oscillation time, output power, and conversion efficiency have been also well examined; and it is shown that a careful control of the beam current and the acceleration voltage is important for the device performance.

DESIGN OF THE HIGH EFFICIENCY CIRCULAR HORN FEED FOR HIGH-POWER MICROWAVE SYSTEM

Design aspects of high efficiency profiled circular horn feeds with smooth wall for the high-power microwave (HPM) system are presented in this paper. The modal content at the circular aperture of horn necessary to closely approximate a linear polarized Gaussian distribution is established. Slope discontinuities along the axis of the horn are then used to generate the necessary waveguide modes with the appropriate amplitudes and phases at the aperture. The performance of the horn is calculated using the mode matching technique. Significant improvement in the performance of radiation over a straight conical horn can be achieved on the premise of high power capacity. The excellent correspondence between the simulations by MMT codes and CSTMWS (CST microwave studio) supports this conclusion.

Theoretical and Experimental Study of Complementary Metal Oxide Semiconductor Inverters under High-Power Microwave Interferences

Abstract In this article, we report a study of the upset effects on complementary metal oxide semiconductor inverters under high-power microwave interferences. By means of SPICE simulations as well as experimental measurements, the output logic voltage waveforms of inverters were investigated through radio frequency pulse injection. A special radio frequency injection test setup was designed. The power level of the radio frequency pulses being directly injected into the inverters can be as high as 45 dBm, and their frequency ranged from 800 MHz to 4 GHz. The experimental results agreed well with the theoretical simulations, such as the variation rules of the output voltages as well as some transient rising time values. Both the theoretical and experimental results indicate that the SPICE models can be used to evaluate the effects of intensive electromagnetic interference on the digital circuits. Particularly, the variation of the susceptibility of complementary metal oxide semiconductor inverters versus the frequency follows the function f2, and a strong frequency suppression effect is also observed at radio frequencies higher than C band. Finally, the threshold level of logic failure can be significantly affected by the input logic state of the inverters.

A wideband four-way power divider/combiner based on substrate integrated waveguide and double-layer finline

A novel wideband four-way divider/combiner based on substrate integrated waveguide (SIW) and double-layer finline is presented. This divider/combiner designed at 29–40GHz is mainly composed of the doublelayer finline transition from waveguide to SIW and the double-microstrip transition from SIW to microstrip. These transitions feature the function of power divider/combiner, as well as the function of transition. The measured power-combining efficiency of this circuit at 35.6GHz is 86%, and the combining efficiency is higher than 75% at 29–40GHz.

Design of a large-orbit electron gun with gradual reversal magnetic field for a W-band permanent magnet peniotron

This paper demonstrates the operating characteristics of an axis-encircling large-orbit electron gun and a corresponding permanent magnet system of a W-band peniotron. The practical novel large-orbit electron beam with axial velocity spread of 5.17%, transverse velocity spread of 1.28%, guiding center deviation ratio 10.7%, and high velocity ratio 2 is designed. The main advantages of such a peniotron in the large-orbit configuration with a permanent magnet system are its compact size, reduced operational gap, and lower cost. Critical characteristics, such as acceleration voltage and the relative axial position of the magnetic system and electrode system have also been well examined and it is shown that a careful control of them is important for the device performance.

Electromagnetic and particle-in-cell simulation studies of megawatt asymmetrical resonant magnetron

Abstract The asymmetrical resonant magnetron has been theoretically analysed and thoroughly simulated in this paper. By introducing the strap breaks and asymmetrical resonant cavity, the weaken field of the interaction zone can increase the interaction efficiency and the enhanced field of the output coupling also can improve the output power. Through the PIC simulation, the electron dynamics theory can be validated, at the same time, the critical characteristics such as the mode competition, output power and the conversion efficiency have been also well examined. The result shows that a careful control of the operating parameters is important for the performance, and this magnetron can finally generate a pure frequency spectrum at 2.9938 GHz with 3.21 MW output power and 43.23% conversion efficiency, respectively. Finally, this megawatt asymmetrical resonant magnetron has been successfully applied in the medical linear accelerator.

A compact high-efficiency power divider/combiner based on quadruple-ridged waveguide

A compact high-efficiency four-way divider/combiner based on quadruple-ridged waveguide is presented. This divider/combiner designed at 31–38GHz is mainly composed of the quadruple-ridged transition, which features four-way power divider/combiner as well as transition from waveguide to microstrip. The measured power-combining efficiency of this circuit at 34GHz is up to 91%, and the combining efficiency is higher than 80% at 31–38GHz.

Correction to “Studies of the Frequency-Agile Relativistic Magnetron” [May 12 1344-1349]

In the above titled paper (ibid., vol. 40, no. 5, pp. 1344-1349, May 2012), none of the references were cited in the text. Listed here are the sentences where the references should have been cited.