共查询到20条相似文献,搜索用时 15 毫秒
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A. van Ardenne 《International Journal of Infrared and Millimeter Waves》1987,8(2):107-117
Conclusion A progress report was given for a multibeam system with only a limited (3–4) number of beams.We have outlined the desirability of larger arrays and some instrumental consquences were considered. We have also shown that extension of the JCMT infrastructure could fulfil the requirements but most of the development need to be done in the frontend segment. 相似文献
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A. A. Vertiy I. V. Ivanchenko N. A. Popenko S. I. Tarapov V. P. Shestopalov 《International Journal of Infrared and Millimeter Waves》1989,10(3):395-404
A radio spectrometer set suggesting wide fuctional possibilities and operating in the shortwave part of the millimeter band at temperatures below 1 K is described. The set is intended for analyzing materials of polarized nuclear targets under the conditions close to actual operation, with the use of magnetic resonance methods. The potential of spectrometer allows employing it in semiconductor physics, physics of disordered media, biology, et.c. 相似文献
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电子光学系统是毫米波速调管长寿命和整管性能实现的关键,毫米波速调管零件尺寸较小,为了在Ka波段和W波段实现千瓦量级的输出功率,要求具有高的电子注通过率及低的阴极负荷。对Ka波段和W波段电子光学系统特性进行了分析,确定了Ka波段10 kW分布作用速调管和W波段1 kW分布作用速调管电子光学系统的设计方案,利用软件对电子枪和聚焦系统的结构进行计算,并采用CST仿真软件对设计的电子枪发射的电子注在聚焦磁场中的状态进行优化。设计出的Ka波段速调管电子光学系统,电子枪工作电压26 kV,发射电流2 A,互作用区长度30 mm,磁场强度大于0.6 T,流通达到100%。设计的W波段速调管电子光学系统,电子枪工作电压17 kV,电流0.65 A,互作用区长度20 mm,磁场大于0.9 T,流通达到100%。已制成Ka波段速调管和W波段速调管,设计的电子光学系统能够满足速调管工程化需求。 相似文献
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Roman Gl?ckler 《International Journal of Infrared and Millimeter Waves》1990,11(2):101-110
A phased array is presented at a frequency of 70 GHz, consisting of a corporate feed, ferrite phase shifters and dielectric rod antennas. Metal waveguides were utilized to construct the feed network, whereas a special dielectric waveguide structure was employed for the ferrite phase shifter and dielectric rod antenna. Beam scanning can be performed electronically controlled in the horizontal plane. 相似文献
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GaAs-based planar Gunn diodes with AlGaAs hot electron injector have been successfully developed to be used as a local oscillator of 76 GHz in monolithic millimeter-wave integrated circuits.We designed two kinds of structure diode,one has a fixed distance between the anode and cathode,but has variational cathode area,the other has a fixed cathode area,but has different distances between two electrodes.The fabrication of Gunn diode is performed in accordance with the order of operations:cathode defining,mesa etching,anode defining,isolation,passivation,via hole and electroplating.A peak current density of 29.5 kA/cm 2 is obtained.And the characteristics of negative differential resistance and the asymmetry of the current-voltage curve due to the AlGaAs hot electron injector are discussed in detail.It is demonstrated that the smaller size of active area corresponds to the smaller current,and the shorter distance between anode and cathode also corresponds to the lower threshold voltage and higher peak current,and hot electron injector can effectively enhance the radio frequency conversion efficiency and output power. 相似文献
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George E. Ponchak Linda P. B. Katehi 《International Journal of Infrared and Millimeter Waves》1997,18(2):369-382
Design rules for Layered Ridge Dielectric Waveguide (LRDW) are presented for the first time through simple figures and closed
form equations. The Effective Dielectric Constant (EDC) method is used to develop the design rules that account for typical
circuit specifications such as higher order mode suppression, dispersion, attenuation, and coupling between adjacent transmission
lines. Comparisons between the design of LRDW, image guide, and millimeter-wave dielectric ridge guide are made. 相似文献
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In this review we consider the composition and placement of receiver complexes on millimeter and submillimeter wave radio
telescopes as well as their components and circuitry. Examples of receiver complexes are given for both ground-based and space
radio telescopes. 相似文献
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N. Kuno H. Matsuo Y. Mizumoto A. E. Lange J. W. Beeman E. E. Haller 《International Journal of Infrared and Millimeter Waves》1993,14(4):749-762
We have fabricated a millimeter wave observation system using an array of bolometric detectors. The performance of the system depends largely on obtaining identical performance from each bolometer. We achieved a variance in the responsivity of less than 4% except for one of the seven elements. The bolometers had an electrical NEP of 1.3×10–16 W/Hz under radiation background loading of 30pW. We used an AC bridge readout circuit to significantly improve the stability of the array and showed that observations can be done without a mechanical beam switch. The bolometer array is now in use on the Nobeyama 45-m telescope for 150GHz observations.H. Matsuo thanks those who helped him work on bolometers during his stay in Berkeley, especially to T. Wilbanks, M. Devlin and C. Inman. The authors are also grateful to S. Sato and T. Watabe at Nagoya University for their advice on the AC bridge circuit. This work is partly supported by the Shimazdu Science Foundation. 相似文献
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The dispersion characteristics of Insulated non-radiative dielectric guides are computed using mode matching technique. From the dispersion characteristics the dielectric loss conductor loss and wave impedances are derived. Effect of metallic walls on trapped insulated image guide are also discussed. The dimensions of Insulated non radiative dielectric guide are same as that of rectangular metallic wave guide at ka band. 相似文献
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从半径渐变波导的耦合波方程出发,利用龙格-库塔法进行优化数值迭代,得到在3 mm波段,TE03-TE02, TE02-TE01高效率模式变换器的设计参数。通过优化程序,设计出了6周期TE03-TE02和3周期TE02-TE01模式变换器优化尺寸。利用CST微波工作室电磁仿真软件对结构尺寸进行优化仿真,仿真结果与优化程序计算结果基本一致。以此数据设计中心频率94 GHz的TE03-TE02,TE02-TE01模式变换器功率转换效率可以达到98.5%以上,90%功率转换的绝对带宽分别达到3.5和7.0 GHz以上,优于设计要求。 相似文献
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从半径渐变波导的耦合波方程出发,利用龙格-库塔法进行优化数值迭代,得到在3 mm波段,TE03-TE02, TE02-TE01高效率模式变换器的设计参数。通过优化程序,设计出了6周期TE03-TE02和3周期TE02-TE01模式变换器优化尺寸。利用CST微波工作室电磁仿真软件对结构尺寸进行优化仿真,仿真结果与优化程序计算结果基本一致。以此数据设计中心频率94 GHz的TE03-TE02,TE02-TE01模式变换器功率转换效率可以达到98.5%以上,90%功率转换的绝对带宽分别达到3.5和7.0 GHz以上,优于设计要求。 相似文献
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Design and development of high linearity millimeter wave traveling-wave tube for satellite communications 下载免费PDF全文
《中国物理 B》2015,(10)
The linearity of the traveling-wave tube is a very important characteristic for a modern communication system. To improve the linearity of the traveling-wave tube at no expense of the saturated output power and overall efficiency, a modified pitch profile combined with a small adjustment of operating parameters is proposed. The optimal design of the helix circuit is evaluated theoretically by a large signal analysis, and the experimental test is also carried out to make a comparison of performance between the novel and original designed traveling-wave tubes. The experiments show that the saturated output powers and efficiencies of these two tubes are close to each other, while the linearity of the traveling-wave tube is obviously improved. The total phase shift and AM/PM conversion at saturation of the novel tube, averaged over the operating band, are only 30.6°/d B and 2.5°/d B, respectively, which are 20.1°/d B and 1.6°/d B lower than those of the original tube, respectively. Moreover, the third-order intermodulation of the novel tube is up to 2.2 d Bc lower than that of the original tube. 相似文献
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Adel A. Ali Ibrahim A. Al-Kadi Mohammad K. Samarkandy 《International Journal of Infrared and Millimeter Waves》1987,8(9):1097-1113
For the CCIR 14-rain climatic zones of the globe, we present a simplified hop length versus fade margin analysis with link reliability as a parameter. The analysis uses Laws-Parsons values for the a and b parameters of A(dB/Km)=a Rb (mm/hr), and considers the two cases of (i) limited rain-cell and (ii) entire hop in rain.The result is a family of fade margin vs. hop length curves for various reliability objectives, obtained for each of the 14-rain zones at a frequency of 50 GHz. A simple frequency scaling rule is also devised to enable similar analysis at frequencies in the range 30–70 GHz.It is particularly concluded that an extended hop length of 10–20 Km is possible with reasonable reliability if the reduced cell-size concept is applied. If the entire hop is in rain, a limited hop length of one to five kms can't be exceeded even with modest reliability. It is also demonstrated that high resolution global rain map, together with an accurate cell size definition are mandatory for reliable radio link design at mm-wave lengths. 相似文献