共查询到20条相似文献,搜索用时 10 毫秒
1.
T. Saito T. Nakano H. Hoshizuki K. Sakai Y. Tatematsu S. Mitsudo I. Ogawa T. Idehara V. E. Zapevalov 《Journal of Infrared, Millimeter and Terahertz Waves》2007,28(12):1063-1078
A 300 GHz CW gyrotron FU CW I has been developed and installed in the Research Center for Development of Far-Infrared Region, University of Fukui as a power source of a high frequency material processing system. Its performance was tested and the maximum power of 1.75 kW / CW has been attained at the beam voltage of 15 kV and the beam current of 1A. The maximum window power efficiency of 15.5% has been obtained at the cathode voltage slightly lower than 15 kV. This gyrotron is designed to deliver a Gaussian beam after mode conversion from the oscillation mode TE22,8 in the cavity with a complex of an internal radiator and beam shaping mirrors. The detailed measurement with an infrared camera has confirmed that a Gaussian beam is radiated when the magnetic field strength B c at the cavity is adjusted at a proper value. However, within a range of B c , the output power is emerged into multiple directions, which suggests simultaneous oscillation of competing cavity modes. 相似文献
2.
Nitin Kumar Mukesh K. Alaria Udaybir Singh A. Bera T. P. Singh A. K. Sinha 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(5):601-607
A beam tunnel for a 42 GHz, 200 kW gyrotron for an Indian TOKAMAK system has been designed. The initial design of the beam
tunnel has been carried out on the basis of the required electron beam parameters at the interaction cavity and the electron
beam simulation of the magnetron injection gun. The design optimization of the beam tunnel has been done with the help of
3-D simulation software CST-Microwave Studio. In the simulation, the absorption, the reflection and the transmission of RF
power by the beam tunnel have been analyzed. Three different lossy ceramics, Al2O3–SiC, AlN–SiC and BeO–SiC have been investigated during the simulation. The simulation results obtained with CST-Microwave
Studio have been validated with another 3-D simulation software HFSS. The Q value of the beam tunnel for different ceramic
material has also been analyzed to investigate the parasitic mode excitation in the beam tunnel. 相似文献
3.
Udaybir Singh Anirban Bera R. R. Rao Ashok K. Sinha 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(4):533-541
In this paper, a synthesized design of the magnetron injection gun (MIG) for a 200 kW, 42 GHz gyrotron is presented. The synthesis
steps involve the selection of the type of the MIG, the development of the design criteria, the selection of initial design
parameters and the development of a program for the estimation of the synthesized parameters for the MIG design. The presented
approach estimates the cathode, the beam and the anode parameters, enabling one to build a synthesis model of a complete MIG
system. 相似文献
4.
David S. Tax Eunmi M. Choi Ivan Mastovsky Jeffrey M. Neilson Michael A. Shapiro Jagadishwar R. Sirigiri Richard J. Temkin Antonio C. Torrezan 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(3):358-370
We present an internal mode converter (IMC) design for a 1.5 MW, 110 GHz gyrotron operating in the TE22,6 mode. The launcher, designed using the codes Surf3d and LOT, converts the cavity waveguide mode into a nearly pure Gaussian
beam. The Gaussian beam output from the launcher is shaped by a series of 4 smooth, curved mirrors to provide a circular output
beam with a flat phase front at the gyrotron window. By employing smooth mirrors rather than mirrors with phase correcting
surfaces, such an IMC is less sensitive to alignment issues and can more reliably operate with high efficiency. The IMC performance
was verified by both cold test and hot test experiments. Beam pattern measurements in each case were in good agreement with
theoretical predictions. The output beam was of high quality with calculations showing that the Gaussian Beam content was
95.8 ± 0.5% in both hot and cold test. 相似文献
5.
Haji Aripin Seitaro Mitsudo I. Nyoman Sudiana Shinji Tani Katsuhide Sako Yutaka Fujii Teruo Saito Toshitaka Idehara Sliven Sabchevski 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(6):867-876
In this paper, we present and discuss experimental results from a microwave sintering of a silica-glass ceramic, produced
from a silica xerogel extracted from a sago waste ash. As a radiation source for the microwave heating a sub-millimeter wave
gyrotron (Gyrotron FU CW I) with an output frequency of 300 GHz has been used. The powders of silica xerogel have been dry
pressed and then sintered at temperatures ranging from 300°C to 1500°C. The influence of the sintering temperature on the
technological properties such as porosity and bulk density was studied in detail. Furthermore, X-ray diffraction (XRD) and
Fourier Transform Infrared (FTIR) spectroscopy have been used in order to study the structure of the produced silica glass-ceramics.
It has been found that the silica xerogel crystallizes at a temperature of 800°C, which is about 200°C lower than the one
observed in the conventional process. The silica xerogel samples sintered by their irradiation with a sub-millimeter wave
at 900°C for 18 minutes are fully crystallized into a silica glass-ceramic with a density of about 2.2 g/cm3 and cristobalite as a major crystalline phase. The results obtained in this study allow one to conclude that the microwave
sintering with sub-millimeter waves is an appropriate technological process for production of silica glass-ceramics from a
silica xerogel and is characterized with such advantages as shorter times of the thermal cycle, lower sintering temperatures
and higher quality of the final product. 相似文献
6.
Sudheer Jawla Qing Zhe Ni Alexander Barnes William Guss Eugenio Daviso Judith Herzfeld Robert Griffin Richard Temkin 《Journal of Infrared, Millimeter and Terahertz Waves》2013,34(1):42-52
In this paper, we describe the design and experimental results from the rebuild of a 250 GHz gyrotron used for Dynamic Nuclear Polarization enhanced Nuclear Magnetic Resonance spectroscopy on a 380 MHz spectrometer. Tuning bandwidth of approximately 2 GHz is easily achieved at a fixed magnetic field of 9.24 T and a beam current of 95 mA producing an average output power of >10 W over the entire tuning band. This tube incorporates a double disk output sapphire window in order to maximize the transmission at 250.58 GHz. DNP Signal enhancement of >125 is achieved on a 13C-Urea sample using this gyrotron. 相似文献
7.
Wenjie Fu Yang Yan Xiaoyun Li Shenggang Liu 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(4):404-410
A 220 GHz gyrotron with an 8 T pulse magnet has been designed, constructed and operated in Terahertz Research Center, University of Electronic Science and Technology of China. TE03 mode is selected as the operation mode, which is less susceptible to the mode competition. Experimental results show the output power is achieved 11.5 kW with efficiencies of 12.8%, and the frequency is between 219.6 GHz and 234.2 GHz. 相似文献
8.
Udaybir Singh Nitin Kumar L. P. Purohit Ashok K. Sinha 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(7):878-883
A 40 A double-anode magnetron injection gun for a 1 MW, 110 GHz gyrotron has been designed. The preliminary design has been
obtained by using some trade-off equations. The electron beam analysis has been performed by using the commercially available
code EGUN and the in-house developed code MIGANS. The operating mode of the gyrotron is TE22,6 and it is operated in the fundamental harmonic. The electron beam with a low transverse velocity spread (db ^max = 2.26% \delta {\beta_{ \bot \max }} = 2.26\% ) and the transverse-to-axial velocity ratio of the electron beam (α) = 1.37 is obtained. The simulated results of the MIG
obtained with the EGUN code have been validated with another trajectory code TRAK. The results on the design output parameters
obtained by both the codes are in good agreement. The sensitivity analysis has been carried out by changing the different
gun parameters to decide the fabrication tolerance. 相似文献
9.
Lin Zou Xuegang Wang Lu Qian 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(11):1390-1397
The Radar Cross Section (RCS) signature of the chaff cloud in the millimeter wave band is useful in many research fields such
as radar countermeasure, target identification and discrimination, and so on. To obtain the RCS of the chaff cloud, practical
measurement is an effective method. This paper introduces the design and implementation of a bistatic radar which is used
for chaff cloud RCS measurement. The configuration of the radar system and the techniques used in this system, including oversampling,
digital down conversion, coherent integration, and interpolation, are discussed. The infield experiment results are presented. 相似文献
10.
Toshitaka Idehara Kosuke Kosuga La Agusu Ryosuke Ikeda Isamu Ogawa Teruo Saito Yoh Matsuki Keisuke Ueda Toshimichi Fujiwara 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(7):775-790
A high frequency gyrotron with a 15 T superconducting magnet named Gyrotron FU CW VI has achieved continuous frequency tuning through the relatively wide range of 1.5 GHz near 400 GHz. The operation is at the fundamental cyclotron resonance of the TE06 cavity mode with many higher order axial modes. The output power measured at the end of the circular waveguide system ranges from 10 to 50 watts at the low acceleration voltage of 12 kV for beam electrons. The beam current is also low. It is around 250 mA. This gyrotron is designed as a demountable radiation source for the 600 MHz DNP-NMR spectroscopy. The design and operation results of the gyrotron FU CW VI are presented. 相似文献
11.
Nitin Kumar Udaybir Singh T. P. Singh A. K. Sinha 《Journal of Infrared, Millimeter and Terahertz Waves》2011,32(2):186-195
The design and the numerical simulation of the 95 GHz, 2 MW gyrotron for various kinds of communication, sensing and security
applications is presented. The gyrotron is designed for the TE24,8 operating mode. Various in-house developed and commercially available computer codes are used for the design purpose. A 4.25 MW
electron gun is designed for the 2 MW of output power. The mode selection, cold cavity and the beam–wave interaction analysis
are discussed for the design of weakly tapered open resonator type of interaction cavity. The parametric analysis of the interaction
cavity and the electron gun is also presented. 相似文献
12.
13.
Nitin Kumar Udaybir Singh Anirban Bera A. K. Sinha 《Journal of Infrared, Millimeter and Terahertz Waves》2017,38(11):1342-1356
In this paper, we present the RF behavior of conventional cylindrical interaction cavity for 240 GHz, 1 MW gyrotron for futuristic plasma fusion reactors. Very high-order TE mode is searched for this gyrotron to minimize the Ohmic wall loading at the interaction cavity. The mode selection process is carried out rigorously to analyze the mode competition and design feasibility. The cold cavity analysis and beam-wave interaction computation are carried out to finalize the cavity design. The detail parametric analyses for interaction cavity are performed in terms of mode stability, interaction efficiency and frequency. In addition, the design of triode type magnetron injection gun is also discussed. The electron beam parameters such as velocity ratio and velocity spread are optimized as per the requirement at interaction cavity. The design studies presented here confirm the realization of CW, 1 MW power at 240 GHz frequency at TE46,17 mode. 相似文献
14.
Kunio Tsutaki Yoichiro Neo Hidenori Mimura Norio Masuda Mitsuru Yoshida 《Journal of Infrared, Millimeter and Terahertz Waves》2016,37(12):1166-1172
For future broadband wireless links, we have designed a 300 GHz band traveling wave tube (TWT) with a folded waveguide fabricated by microelectromechanical systems (MEMS). The TWT operates at a beam voltage of 12 kV and a beam current of 8.3 mA. The classical large signal simulation code predicts the output power greater than 1 W and gain larger than 20 dB over the bandwidth from 280 to 300 GHz. 相似文献
15.
M. D. Proyavin M. Yu. Glyavin V. N. Manuilov 《Journal of Communications Technology and Electronics》2017,62(10):1165-1171
It is shown that it is possible to use warm solenoids with copper winding screened with ferromagnetic shields in order to reduce the solenoid supply power by a factor of 1.8–2 while retaining the strength of the magnetic field in the working space for continuous gyrotrons operating in a frequency range of 24–30 GHz. The configuration of the shields as well as the shape and location of the correcting solenoids providing an extended (up to 10 wavelengths long) section of a uniform field in the region of the gyrotron cavity have been determined. It has been shown that introduction of an additional cathode coil into the magnetic system reduces the degree of nonadiabaticity of the magnetic field approximately by an order of magnitude and thereby makes it possible to use the magnetron injection gun for formation of a helical electron beam. Optimization of the configuration of the gun electrodes based on the trajectory analysis makes it possible to obtain an electron beam whose parameters are as good as parameters of the electron beams formed in classical adiabatic electron–optical systems of gyrotrons. 相似文献
16.
17.
Mauro Angelini Marco Frasca Massimiliano Rossi 《Signal, Image and Video Processing》2016,10(7):1241-1247
This paper describes the design and realization of a W-band radiometric sensor and its imaging performance obtained during indoor and outdoor experimental trials. The system has been used both in indoor and in outdoor scenarios in near-radiative and far-field conditions, respectively. 相似文献
18.
Mamoru Kamikura Masato Naruse Shin’ichiro Asayama Naohisa Satou Wenlei Shan Yutaro Sekimoto 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(6):697-707
We present design and evaluations of a submillimeter double-ridged waveguide ortho-mode transducer (OMT) for ALMA Band 8 (385–500 GHz)
cartridge receiver. The measured transmission loss of the OMT at 4 K was 0.4–0.5 dB according to noise measurements with an
SIS mixer. The polarization isolation was measured to be larger than 29 dB from quasioptical measurements. The OMT consists
of a Bϕifot junction and a double-ridged guide. A robust design with allowable mechanical errors of 20 μm has been demonstrated. 相似文献
19.
Deployment of an efficient cellular network is considered as a challenging task as it affects the performance measures like data rate, bit error rate, spectrum efficiency and energy efficiency etc. For this, the foremost important step is developing an accurate path loss model for the network in the deployment region. In this paper, an empirical path loss model is estimated for an IEEE 802.16e standardised WiMAX network operating on a carrier frequency of 2.65 GHz deployed in a sub-urban area. An experimental setup is designed for collecting the parameters such as carrier to interference plus noise ratio (CINR), received signal strength indicator (RSSI) for the concerned network and with the help of regression technique, the path loss model is formulated. The relationships between CINR, RSSI, and the distance between base station and customer premise equipment are formulated. The distributions of RSSI, CINR and path loss for the concerned network are also found out. Then by using the proposed path loss model, link budget analysis is performed. From the analysis, it is concluded that the proposed path loss model closely approximates to Stanford University Interim model with path loss exponent value of 3.45. 相似文献