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排序方式: 共有153条查询结果,搜索用时 984 毫秒
1.
Gashinova M.S. Goubina M.N. Guoyong Zhang Kolmakov I.A. Kolmakov Y.A. Vendik I.B. 《Microwave Theory and Techniques》2003,51(3):792-795
This paper presents design and measurement results of a high-T/sub c/ superconducting planar filter based on a pair of coupled modified hairpin resonators considered to be a key constituent of the filter structure. This provides the filter characteristics, which are very close to the Chebyshev prototype of the same order. 相似文献
2.
玻璃划线机设备是液晶生产线上的主要设备之一,在一定程度上决定着LCD产品的最终质量。该机主要是用于对大块或断条后的成盒玻璃进行划线,主要介绍了DHJ-500多刀玻璃划线机的概况、机械总体结构设计和电气控制设计等。 相似文献
3.
4.
Vendik I.B. Vendik O.G. Kollberg E.L. Sherman V.O. 《Microwave Theory and Techniques》1999,47(8):1553-1562
A theory of digital phase shifters based on transition from a superconducting (S) state into a normal (N) state in high-Tc superconductor (HTS) films is developed. It is shown that the insertion-loss level in the phase shifters is determined by the commutation quality of the HTS film and does not depend on the S-N switching element shape and size. The procedure for designing the S-N phase shifter with minimum insertion loss is equivalent to designing a matching circuit for the termination Z=√RSRN (RS and RN are the resistances of the switching element in the S- and N-states, respectively). Different versions of S-N phase shifters are suggested and discussed. High-quality S-N phase shifters can be successfully designed in a 1-10 GHz frequency range and find application on the receiving end of microwave systems 相似文献
5.
We consider a microwave phase shifter based on thin-film ferroelectric parallel-plate capacitors operating as a part of a
phased array at an elevated microwave power level and for a limited power in the control circuits. To eliminate capacitance
modulation in parallel-plate capacitors by an ac field, we propose the separation of the effects of the dc control voltage
and the ac voltage based on the symmetry of the capacitance-voltage characteristic of the unit including two capacitors parallel-connected
in the ac voltage U
ac and series-connected in dc voltage U
dc. The experiment shows that for U
dc > U
ac, the phase of the wave passing through the phase shifter weakly depends on the microwave signal power. The reflection phase
shifter is tested for a pulsed power of the microwave signal up to 6 W and a power in the control circuit on the order of
10 μW. 相似文献
6.
An analytical expression for calculating the wave parameters of a narrow-slot transmission line is found in the quasistatic
approximation. A two-fluid model is used for analyzing processes in a superconducting film of thickness comparable to the
London penetration depth. The wave parameters of the slotted line are calculated under assumptions about the current distribution
near the edges of the slot which are analogous to those used previously for analyzing microstrip and coplanar lines.
Zh. Tekh. Fiz. 67, 94–97 (September 1997) 相似文献
7.
The simple closed-form model of nonlinear response of a high-temperature superconducting disk resonator on microwave power is proposed. The model is based on superconducting film nonlinearity and describes the dependence of unloaded quality factor on the incident power. The specified normalizing power is used as the only fitting parameter. Good quantitative agreement of modeled and measured data has been obtained. The results observed exhibit the kinetic nature of the nonlinearity of the disk resonator on an LaAlO3 substrate at T=60 K and more complicated, presumably thermal, heating nature of the nonlinearity at lower temperature 相似文献
8.
9.
Metamaterials and their application in microwaves: A review 总被引:1,自引:0,他引:1
A metamaterial is a composite material that has attracted the attention of researchers since the late 1990s-early 2000s. This material contains an artificial periodic structure, which modifies its permittivity and permeability and, thereby, makes it possible to control the dispersion, refraction, and reflection of electromagnetic waves in the metamaterial. Analytical and experimental studies of the properties of metamaterials, as well as their applications, cover a wide frequency range from radio waves to the visible range. In recent years, considerable progress has been made toward the application of these materials in the microwave range (1–100 GHz). Works on development and application of metamaterials in the microwave range published over the last 8–10 years are reviewed. Artificial transmission lines as 1D metamaterials are discussed. Resonators, filters, and phase shifters based on the “metamaterial philosophy” are considered. Special attention is given to the application of metamaterials in the antenna technology. 相似文献
10.
为提高土壤多元素同时检测的效率,采用超级微波消解-电感耦合等离子体发射光谱法测定土壤中钾、钠、钙、镁、铜、铁、锰、锌、磷、硫、硼、砷、镉、铬、铅、钴、镓、锂等18种元素含量。比较了超级微波消解、常规微波消解和电热板消解的处理效果,采用超级微波消解法对样品进行前处理,并优化了消解条件。在最优条件下,各元素的检出限在0.05~20 mg/kg,加标回收率在86.2%~107.5%,RSD在0.1%~3.0%,方法准确度及精密度可以满足多元素同时测定的需求,且该方法具有简单、快速、成本低、用酸量少、重现性好等特点。 相似文献