scholarly journals Over-Size Pill-Box Window for Sub-Terahertz Vacuum Electronic Devices

Electronics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 653
Author(s):  
Tongbin Yang ◽  
Xiaotong Guan ◽  
Wenjie Fu ◽  
Dun Lu ◽  
Chaoyang Zhang ◽  
...  
Keyword(s):  
High Frequency ◽  
Transmission Loss ◽  
Electronic Devices ◽  
Circular Waveguide ◽  
Influential Factor ◽  
Experimental Result ◽  
Operating Frequency ◽  
Bottom Surface ◽  
Frequency Bands ◽  
Vacuum Electronic Devices

The pill-box window is one of the important components of microwave vacuum electronic devices (VEDs), and research into it is of great significance. As the operating frequency increases, the problems associated with the reduction in the structure size include the reduction of the brazing plane and the reduction in the tolerance of the pill-box window. These problems will cause traditional pill-box windows to be unsuitable in high-frequency bands, especially in terahertz and sub-terahertz regions. The most influential factor is the length of the circular waveguide in the box window. The welding plane of the over-size pill-box window is the annular bottom surface on both sides of the dielectric sheet, which is larger than the circular waveguide, and the operating frequency does not directly affect the area of the brazing surface. Choosing a suitable diameter for the dielectric sheet can effectively increase the tolerance to the length of the pill-box window circular waveguide. Therefore, an over-size pill-box window would be a practicable approach to improve the performance compared to the traditional pillow-box in high-frequency bands. This paper describes, in detail, the theoretical design, simulation optimization and experimental process of this improved pill-box window. An over-size pill-box window suitable for G band VEDs was successfully developed. The experimental result in the 215–225 GHz band is that the maximum transmission loss is −1 dB, and the overall transmission loss is close to −0.5 dB. The overall reflection is less than −11 dB.

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

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 103
Author(s):  
Tongbin Yang ◽  
Xiaotong Guan ◽  
Wenjie Fu ◽  
Dun Lu ◽  
Xuesong Yuan ◽  
...  
Keyword(s):  
High Frequency ◽  
Circular Waveguide ◽  
Simulation Software ◽  
Frequency Deviation ◽  
Mode Converter ◽  
Experimental Result ◽  
Te01 Mode ◽  
Mode Converters ◽  
Simulation And Experiment ◽  
Mode Purity

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.

Model for Estimating Effects of Human Body Shadowing in High Frequency Bands

2015 ◽  
Vol E98.B (5) ◽  
pp. 773-782 ◽  
Author(s):  
Ngochao TRAN ◽  
Tetsuro IMAI ◽  
Yukihiko OKUMURA
Keyword(s):  
Human Body ◽  
High Frequency ◽  
Frequency Bands

Terahertz Radiators Based on Si~3C-SiC MQW IMPATT Diodes

2020 ◽  
Vol 10 (4) ◽  
pp. 501-506
Author(s):  
Monisha Ghosh ◽  
Arindam Biswas ◽  
Aritra Acharyya
Keyword(s):  
High Frequency ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Noise Performance ◽  
Rf Power ◽  
Drift Diffusion ◽  
Frequency Bands ◽  
Atmospheric Window ◽  
Lower Noise ◽  
Impatt Diodes

Aims:: The potentiality of Multiple Quantum Well (MQW) Impacts Avalanche Transit Time (IMPATT) diodes based on Si~3C-SiC heterostructures as possible terahertz radiators have been explored in this paper. Objective:: The static, high frequency and noise performance of MQW devices operating at 94, 140, and 220 GHz atmospheric window frequencies, as well as 0.30 and 0.50 THz frequency bands, have been studied in this paper. Methods: The simulation methods based on a Self-Consistent Quantum Drift-Diffusion (SCQDD) model developed by the authors have been used for the above-mentioned studies. Results: Thus the noise performance of MQW DDRs will be obviously better as compared to the flat Si DDRs operating at different mm-wave and THz frequencies. Conclusion:: Simulation results show that Si~3C-SiC MQW IMPATT sources are capable of providing considerably higher RF power output with the significantly lower noise level at both millimeter-wave (mm-wave) and terahertz (THz) frequency bands as compared to conventional flat Si IMPATT sources.

Comparative analysis of existing methods for improving reliability of vacuum electronic devices

2019 ◽  
pp. 38-41
Author(s):  
A. A. Korneev
Keyword(s):  
Comparative Analysis ◽  
Electronic Device ◽  
Electronic Devices ◽  
Import Substitution ◽  
Electronic Control ◽  
Electronic Control System ◽  
Vacuum Electronic Devices ◽  
Electric Vacuum ◽  
Rational Control ◽  
Complex Technical Systems

The article presents the results of the study of the filament modes of electronic lamps and ensuring the rational temperature of the cathode. A brief description and comparative analysis of existing methods with the proposed author are given. The dependence diagrams obtained as a result of a real experiment are presented. A new method of rational control of the electric vacuum devices (EVP) filament mode is proposed, thereby increasing the reliability and increasing the durability of the EVP during operation in high-quality and expensive complex technical systems. According to the results of the study, a new specialized electronic device was developed, which allowed to smoothly regulate the supply of the filament voltage, thereby ensuring the rational control of the operation of the EVP. The technique and specialized electronic device are developed on the basis of modern scientific and technical achievements. This made it possible to increase the reliability and efficiency of the electronic control system for solving critical tasks. When implementing the developed device, the problem of import substitution was solved.

scholarly journals A Low-Profile HF Meandered Dipole Antenna with a Ferrite-Loaded Artificial Magnetic Conductor

2021 ◽  
Vol 11 (5) ◽  
pp. 2237
Author(s):  
Oh Heon Kwon ◽  
Won Bin Park ◽  
Juho Yun ◽  
Hong Jun Lim ◽  
Keum Cheol Hwang
Keyword(s):  
High Frequency ◽  
Dipole Antenna ◽  
Unit Cell ◽  
Operating Frequency ◽  
High Permeability ◽  
Magnetic Conductor ◽  
Artificial Magnetic Conductor ◽  
Low Profile ◽  
Compact Size ◽  
Binary Genetic Algorithm

In this paper, a low-profile HF (high-frequency) meandered dipole antenna with a ferrite-loaded artificial magnetic conductor (AMC) is proposed. To operate in the HF band while retaining a compact size, ferrite with high permeability is applied to the unit cell of the AMC. The operating frequency bandwidth of the designed unit cell of the AMC is 1.89:1 (19–36 MHz). Thereafter, a meandered dipole antenna is designed by implementing a binary genetic algorithm and is combined with the AMC. The overall size of the designed antenna is 0.06×0.06×0.002 λ3 at the lowest operating frequency. The proposed dipole antenna with a ferrite-loaded AMC is fabricated and measured. The measured VSWR bandwidth (<3) covers 20–30 MHz on the HF band. To confirm the performance of the antenna, a reference monopole antenna which operates on the HF band was selected, and the measured receiving power is compared with the result of the proposed antenna with the AMC.

scholarly journals How Good Is the STW Sensor? An Account from a Larger Shipping Company

2021 ◽  
Vol 9 (5) ◽  
pp. 465
Author(s):  
Angelos Ikonomakis ◽  
Ulrik Dam Nielsen ◽  
Klaus Kähler Holst ◽  
Jesper Dietz ◽  
Roberto Galeazzi
Keyword(s):  
High Frequency ◽  
Additional Data ◽  
Empirical Method ◽  
Influential Factor ◽  
Sensor Data ◽  
Sea State ◽  
Shipping Company ◽  
Frequency Sensor ◽  
Semi Empirical

This paper examines the statistical properties and the quality of the speed through water (STW) measurement based on data extracted from almost 200 container ships of Maersk Line’s fleet for 3 years of operation. The analysis uses high-frequency sensor data along with additional data sources derived from external providers. The interest of the study has its background in the accuracy of STW measurement as the most important parameter in the assessment of a ship’s performance analysis. The paper contains a thorough analysis of the measurements assumed to be related with the STW error, along with a descriptive decomposition of the main variables by sea region including sea state, vessel class, vessel IMO number and manufacturer of the speed-log installed in each ship. The paper suggests a semi-empirical method using a threshold to identify potential error in a ship’s STW measurement. The study revealed that the sea region is the most influential factor for the STW accuracy and that 26% of the ships of the dataset’s fleet warrant further investigation.

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