Research On Theory And Forward Design Technology Of TWTs

Traveling wave tube amplifiers(TWTs) have became to be the most important microwave/millimeter wave vacuum electronic device in military, for their broad bandwidth, high power, high efficiency, high gain and good flexibility and reliability. In recent years, with the developing of electronic warfare equipment and Phased array radar technology, and the rising of the microwave power module(MPM)which called super device, new requirements on the performance of TWTs is proposed. However, when the performance of TWTs proved, the high-frequency circuits and beam wave interaction distribution are also becoming more and more complex, making the difficulty of the design of TWTs increasing, especially the TWTs using in MPM. Thus, in order to improve the forward design of TWTs, the following contents have been done:(1)Based on the TWTs design experience, this thesis puts emphasis on the electrical parameters design of TWTs, including allocation of efficiency, DC current and voltage, phase velocity and the helix size, while providing the numerical formulas. Then the thesis researched how the panel affecting the characteristics of the high-frequency circuit, and compared the high-frequency characteristics of fan-shaped panel, T-shaped panel and the clamped panel, under the same condition of dispersion, which providing guidance for choosing high-frequency circuit. Based on the analysis of the beam wave interaction, the thesis summarized the methods of improving the efficiency of the TWTs, and then analyzed how the double jump helix distribution impacting on the efficiency and second harmonic qualitatively.(2)Based on Pierce small signal theory, the thesis deduced the special dispersion and coupling impedance shaped principle used in broadband TWTs, and proposed the special dispersion and coupling impedance shaped technology for broadband TWTs design, when giving the design flow, and the method was verified by the example of the design of corresponding TWTs. Comparing with the ordinary design technologies, the special dispersion and coupling impedance shaped technology has separated the design of the high-frequency circuit and the beam wave interaction distribution, which avoided the repeated iteration between the high-frequency circuit and the beam wave interaction distribution, thus the design efficiency of TWTs and design success rate is improved greatly.(3) In the thesis, a high-frequency circuit and beam wave interaction distribution of a 2-6GHz miniaturization TWT used in MPM has been designed successfully. And the thesis verified the numerical formulas and design technology given in section(1) and section(2) during the design of the TWT.