Quasi-Optical Mode Converter Based on All-Dielectric Metamaterial for High-Order Mode Vacuum Electronics Devices

Han, Meng; Fu, Wenjie; Lu, Dun; Zhang, Chaoyang; Hu, Shijie; Yan, Yang

doi:10.1109/ted.2022.3224885

Cited by 2 publications

(4 citation statements)

References 32 publications

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“…Due to the rapid urbanization and industrialization of human civilization, UHI is one of the significant problems of the 21st century [40][41][42]. To measure the effect of UHI, UHII is used.…”

Section: Discussionmentioning

confidence: 99%

An Analysis of the Spatial and Temporal Evolution of the Urban Heat Island in the City of Zhengzhou Using MODIS Data

Dang

Kim

2023

Applied Sciences

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A rapid increase in urbanization has caused severe urban heat island (UHI) effects in China over the past few years. Zhengzhou is one of the emerging cities of China where residents are facing strong impact of UHI. By utilizing MODIS data on land surface temperature (LST) and employing 3S technology, this study investigates the UHI phenomenon in Zhengzhou over a 10-year period (2012–2021), aiming to analyze the spatio-temporal evolution characteristics of the UHI effect and the associated land cover changes. To the best of our knowledge, this study represents the first attempt to investigate annual and seasonal changes in different areas of Zhengzhou. It is noted that in the night-time, the intensity of the heat island is stronger than in daytime, which has moderate and weak heat island areas. Seasonal variation showed that in autumn, Zhengzhou has the strong heat island intensity, followed by summer, and the lowest is in winter and spring. The analysis reveals that built-up (construction) areas exhibit the highest LST, whereas forested land and water bodies have the lowest temperature levels. The findings of this study can serve as reference for reducing UHI and increasing thermal comfort in cities.

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Section: Discussionmentioning

confidence: 99%

An Analysis of the Spatial and Temporal Evolution of the Urban Heat Island in the City of Zhengzhou Using MODIS Data

Dang

Kim

2023

Applied Sciences

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“…• -TE 01 • mode converters [5] were used. Due to a lack of circular waveguide calibration parts, the VNA was calibrated using WR28 waveguide calibration parts.…”

Section: Experimental Verificationmentioning

confidence: 99%

“…The total axial length of the manufactured sample was approximately 55 mm (about six times the operating wavelength), including a coupling section with a length of 33 mm and an input and output section, both with lengths of 11 mm. In this experiment, an AV7632C (10 MHz-43.5 GHz) vector network analyzer (VNA) and two Ka-band TE10°-TE01° mode converters [5] were used. Due to a lack of circular waveguide calibration parts, the VNA was calibrated using WR28 waveguide calibration parts.…”

Section: Experimental Verificationmentioning

confidence: 99%

“…As the operating frequency extends to millimeter-wave and terahertz bands, the power capability reduces as the size of the interaction circuits shrinks [4]. Therefore, in order to obtain sufficient power capability and high output power, operating in high-order mode is proposed and attempted in a large number of research works [5][6][7][8][9][10][11][12]. For example, the TM 01 mode is commonly employed for BWOs [7], the TE 0n mode or higher-order TE mn mode is adopted for gyrotrons [8], and the TE n1 mode is usually utilized for the relativistic magnetrons [9].…”

Section: Introductionmentioning

confidence: 99%

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A Compact Circular Waveguide Directional Coupler for High-Order Mode Vacuum Electronic Devices

Zhu,

Fu,

et al. 2024

Electronics

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In this paper, a compact circular waveguide directional coupler for high-order mode vacuum electronic devices is presented and investigated. To reduce the size, the primary and secondary waveguides of this coupler are connected in an orthogonal way by two coupling holes. Moreover, to improve the directivity and operating bandwidth, a method of loading adjustable metal stubs on the isolating port is proposed and introduced in design. A Ka-band TE01-mode circular waveguide directional coupler was designed, and the structure parameters were optimized by electromagnetic simulation. To verify the design, a prototype sample was fabricated, assembled, and tested. The experimental results show good agreement with the simulations, and the directivity are improved by adjusting the metal stubs on the isolating port. In the experiment, a 26.7 dB directivity at 35 GHz was obtained, and the bandwidth of directivity above 20 dB was higher than 7 GHz, corresponding to a relative bandwidth higher than 20%. Meanwhile, the TE01° mode maintained good transmission efficiency in this compact high-order mode directional coupler.

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Quasi-Optical Mode Converter Based on All-Dielectric Metamaterial for High-Order Mode Vacuum Electronics Devices

Cited by 2 publications

References 32 publications

An Analysis of the Spatial and Temporal Evolution of the Urban Heat Island in the City of Zhengzhou Using MODIS Data

An Analysis of the Spatial and Temporal Evolution of the Urban Heat Island in the City of Zhengzhou Using MODIS Data

A Compact Circular Waveguide Directional Coupler for High-Order Mode Vacuum Electronic Devices

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