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The paper presents the results of numerical modeling of the structure composed of spirals winding in different directions. It is shown that this structure has frequency-selective properties and allows controlling the behavior of the reflected wave.
The problem of designing stock-produced EHF-and UHF bandpass filters is considered. Frequency dependences of the parameters of used elements and circuit boards as well as spurious wiring parameters are described. The selection of the filter design circuit is motivated. Typical amplitude-frequency characteristics and their dependence upon the percentage scatter of nominal values of used elements are...
A method for optimizing a microstrip hairpin bandpass filter by changing the angle between the coupled-line sections in order to reduce the insertion and return losses is proposed in the HFSS. The method is based on building filter's sections in different relative coordinate systems whose parameters depend on the value of the angle between the coupled-line sections.
The new filters and diplexers for satellite radio navigation system based on low and high pass filter are presented. Each filter has the broad stopband and low signal power losses in the passband. Location of the bands is chosen to cover the GPS and GLONASS ranges L1 and L2 and provide resolution between each other. In the article the plots characteristics of diplexers and filters transmission gain...
The experimental study results and PC analysis of microstrip hairpin filters on quarter-wave resonators are presented. Some recommendations to get optimum performance are given.
A principle of the microstrip directional traveling-wave filters (MDFTW) scattering parameters formation is discussed and justified on the basis of its known flow diagram. The S-matrix of microstrip directional filter is shown.
The present paper concerns the universal small case for transceivers from the composition of radio-relay stations [1], for transmitters from the composition of wireless systems of digital TV transmission [2, 3] and for multimedia systems of data transmission [4, 5].
All the stages of service lifecycle are briefly discussed. Gaps in the state-of-the-art in the fields of workflows design, their transformation from one notation into another, their analysis, monitoring and re-configuration are also considered. Main methodological solutions for closing the discovered gaps are proposed.
With the increasing popularity of stream-based information sources on the Web, a seemingly continuous and endless flow of messages is generated and propagated to the users. This makes it important to provide systems for reducing the information load on users by employing filtering and ranking techniques. Constructing such systems is an important task in the research domain of Internet Information...
The present paper concerns the architecture of four digital TV units on the base of which Beta TV com Enterprise produces equipment of DVB-C, S, T signal forming.
The paper presents the main points on which a new implementation of the numerical model of an ohmic metal-semiconductor contact was built. As a result of computational experiments the current-voltage characteristics of contact and fields distribution were obtained, indicating the reliability of the model.
We studied temperature dependences of resistivity ρc(T) of Pd-Ti-Pd-Au ohmic contacts to wide-gap semiconductors n-GaN and n-AlN with high dislocation density. The obtained dependences cannot be explained by the existing mechanisms of current flow. We propose possible mechanisms explaining the experimental ρc(T) curves for ohmic contacts to n-GaN and n-Al N.
It was shown that in the region of direct current with Uf>qϕb there is the negative resistance part at static VAC of rectifying metal-semiconductor junctions. Theoretical calculation reveals that negative resistance on the direct brunch of VAC is caused by potential step in order to transfer ballistic electrons through a thin base (∼0.1 um) of the diode. Analysis of transferring time τT(E) and...
As a part of the scientific cooperation between Ukraine and Russia, a series of studies on the preparation of the ground segment of the RadioAstron mission has been carried out. A scientific program of measurements to be performed using the 22-m RT-22 radio telescope (Crimean Astrophysical Observatory) has been prepared. A substantial part of this program is the study of compact structures in extragalactic...
The ground-calibration complex for land-based assessment of the space-based SAR characteristics is designed and developed. Flight tests of the complex are successfully conducted.
There are theories which state that a space of possible orbits in gravitational systems of planetary type is discrete, so there are systems of stable and unstable orbits. A discrete structure of gravitational systems of planetary type should be evident in distributions of orbital energy, angular momentum and some elements of orbits. The easiest way to test such theories is to look for harmonic components...
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