Demonstration of a High-Order Mode Input Coupler for a 220-GHz Confocal Gyrotron Traveling Wave Tube

Guan, Xiaotong; Fu, Wenjie

doi:10.1007/s10762-017-0458-y

Cited by 4 publications

(1 citation statement)

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“…In order to study the performance of the tested mode converter more clearly, some frequency points of 215-225 GHz in the working bandwidth of the mode converter are selected for electric field scanning. Formula (8) can be used to calculate the mode purity of the input and output ports of the mode converter [16]. The calculation results of the purity of the electric field component measured by the input and output ports in the working frequency band is shown in Figure 8a.…”

Section: Experimental Demonstrationmentioning

confidence: 99%

Investigation on 220 GHz Taper Cascaded Over-Mode Circular Waveguide TE0n Mode Converter

Yang

Guan

et al. 2021

Electronics

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This paper proposes a taper cascaded over-mode circular waveguide TE0n mode converter for the millimeter and terahertz wave gyrotron. The mode converter of this structure can effectively reduce the difficulty of high frequency mode converter in fabrication. This paper verifies the feasibility of this new structure from theory, simulation, and experiment. Based on coupled wave theory calculations, three TE02-TE01 mode converters with lengths of 65.43 mm (4 segments), 119.3 mm (6 segments) and 136 mm (8 segments) and a TE03-TE02 mode converter with a length of 92 mm (8 segments) are optimized. The conversion efficiency in the frequency band 215–225 GHz is 91.8–94%, 93–95%, 95–98.78% and 95–98.44%. Because the length of the mode converter is clearly limited, this paper selects the TE02-TE01 mode converter with a length of 65.43 mm (4 segments) and the TE03-TE02 mode converter with 92 mm (8 segments) for simulation and experimental verification. In the simulation software Computer simulation technology (CST), the TE02-TE01 and TE03-TE02 mode converters and their composed TE03-TE01 mode converters are selected for modeling and analyzing. The simulation results and theoretical calculation results of the three mode converters only have different degrees of frequency deviation, and the frequency deviation of the 4-stage TE02-TE01 mode converter can be ignored; the frequency deviations of TE03-TE02 mode converter and TE03-TE01 mode converter are 2 GHz and 3 GHz, respectively. The experimental system is a field scanning system based on a vector network analyzer (VNA), which scans the input and output of the mode converter respectively. The experimental result is that when the input mode purity is 92% in TE01 mode, the output mode TE03 mode has a mode purity of 82%, and it has lower transmission loss. In this paper, the results from theory, simulation and experiment are in good agreement. This type of mode converter is easy to prepare, which makes it an effective alternative for high frequency curvilinear waveguide mode converter.

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Section: Experimental Demonstrationmentioning

confidence: 99%