Theoretical And Experimental Study Of New Slow Wave System For Ka-band

The folded waveguide has the characteristics of frequency bandwidth, easy processing and large power capacity, so it has been widely concerned and has wide application in national defense safety,scientific research and satellite communication.The slow wave system acts as the core component of the injection-wave interaction in the traveling wave tube, and its performance level determines the level of the whole traveling wave tube. However, due to the traditional folded waveguide slow wave structure of the coupling impedance is low, limiting the output power of the upgrade.In order to improve the output power and gain of the folded waveguide parameters, this paper presents a novel Ka-band double ridge loaded FWTWT. The dispersion and coupling impedance characteristics are analyzed by using the electromagnetic simulation software HFSS, and the injection - wave interaction process of this new type traveling wave tube is simulated by the three - dimensional particle simulation software CST. It is concluded that its coupling impedance is higher than that of the conventional zigzag wave, While the electronic efficiency and gain are also higher. The main work of the paper is as follows:1. Design of Ka-band new type of double spine waveguide slow wave structure. I have describe the theory of high frequency characteristics of the slow wave structure, on the high frequency characteristics were simulated using the HFSS simulation software of high frequency, study the effect of structural size on high frequency characteristics.Compared with the conventional folded waveguide slow wave structure, it is found that the slow wave structure has higher coupling resistance than the conventional folded waveguide slow wave structure.2. I have designed the input and output structure and attenuator of the wave tube.The transmission characteristics of the folded wave ridge waveguide structure are simulated by HFSS high frequency simulation software. The voltage standing wave ratio of the tube is less than 1.3, and the CST particle working chamber The results show that the new double-ridge-loaded folded waveguide has 450W output power near the center frequency of 30GHz, the gain is 40.7dB, and the output power is 400W in the range of 29～31GHz,the electronic efficiency is greater than 10%.3. I have study the Ka-band new double-ridge loading folded waveguide experimental, with UG software mapped the on the input and output structure, the slow wave and attenuator, and assembly test, the experimental data and software simulation results are consistent.4. I have designed of a novel double ridge loaded waveguide slow wave structure loaded with metamaterials in this paper. And i have simulated and optimized of the dispersion and coupling impedance of the structure through 3D electromagnetic simulation software HFSS. And compared with the conventional folded waveguide, it is found that the size of structure is 1.2 times as that of ordinary folded waveguide, it is of great convenience for folded waveguide processing. Then, the ORION software is used to simulate the new structure. The simulation results show that the output gain is greater than 37dB and the output power is greater than 410W, which is the reliable basis for the later design.