Study On Double Cavity Parallel Structure Of A 0.14 THz Extended Interaction Oscillator

The frequency range of THZ wave is located at the intersection of electronics and photonics,and its properties show a series of particularities different from other radiation;the Extended Interaction Oscillator(EIO)is a very important THZ wave radiation source.In addition,terahertz radiation sources in the frequency range of 0.1THz-10THz are in increasing demand in the fields of plasma diagnosis,materials science,radiotherapy,advanced communication,etc.,and 0.14THz is one of the four atmospheric Windows,and in the near future,this frequency band can be used for sixth generation communication.In this thesis,a series of theoretical and simulation studies are carried out on the 0.14THz multi-cavity parallel extended interaction oscillator.The specific work is as follows:1.Based on the working principle and characteristics of EIO,some characteristic parameters,such as coupling impedance,quality factor and dispersion characteristics,are described2.For single-cavity structure EIO,the CST software is used to conduct a cold cavity analysis,where the structural parameters are adjusted to determine the correlation between the electric field,coupling impedance,quality factor,and dispersion of the high-frequency structure.On this basis,particle simulation software MAGIC is used to simulate the particles from the two aspects of whether to consider metal loss.and the appropriate working voltage and output structure parameters are determined.Based on the results,it is found that the maximum output power of 485W can be achieved when the operating voltage is 12.6k V,the current density is 100A/cm~2,the magnetic field intensity is 0.5T,and the period number is 11,without considering the metal loss.Additionally,considering the metal loss,when the working voltage is 12.4k V,the current density is 200A/cm~2,the magnetic field intensity is 0.5T,and the period number is 17,the maximum output power of 195W.3.The double-cavity parallel structure EIO is introduced.Firstly,the eigen mode of the structure is calculated by using the software CST,and the relationship between the dispersion,electric field,coupling impedance quality factor and structural parameters of the high-frequency structure is analyzed.Then,the particle simulation software MAGIC is used to carry out the simulation calculation from the two aspects of whether there is metal loss,when the loss is not considered,the effects of coupling hole height,rectangular connection structure parameters and outlet position on the output performance are analyzed.The results show that when the voltage is 12.6k V,the current density is100A/cm~2,the magnetic field intensity is 0.5T,and the outlet position is in the sixth gap,the maximum output power is 751W,which is 54.8%higher than the single cavity without loss.When considering the metal loss,the influence of the number of periods and working voltage on the output performance is analyzed.The results show that when the number of periods is 13,the voltage is 12.6k V,the current density is 200A/cm~2,and the magnetic field intensity is 0.5T,the output power reaches the maximum of 366W,which is 87.69%higher than the single cavity without loss.In addition,on the basis of the dual output structure,the power fusion of the two output structures is used to output the power.The obtained results show that when the working voltage is 12.6k V,the current density is100A/cm~2,the magnetic field intensity is 0.5T,and the number of periods is 11,the output power is 1480W without considering the loss.When the loss is considered,the output power is 600W when the working voltage is 12.6k V,the current density is 300A/cm~2,the magnetic field intensity is 0.5T,and the number of periods is 11,which is about twice the output power of single-cavity EIO under the same current density.Finally,a simple design and calculation of the double strip EIO injection electron gun is carried out,and the error range of the allowable tilt angle of the square plate cathode is obtained.Through a series of cold cavity analysis and particle simulation calculation,the output power of 0.14THz single cavity structure EIO is 195W and 0.14THz double cavity parallel structure EIO is 366W,and the power of double output structure is fused by power fusion method.Finally,the output power is 600W.It breaks through the limitation of traditional EIO in power.