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1
Content available remote

Temperature Stability of Coaxial Cables

100%
Czuba K., Sikora D.
Acta Physica Polonica A
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2011
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vol. 119
|
issue 4
553-557
EN
Radio frequency systems developed for large scientific experiments have become increasingly sensitive to phase changes in their subcomponents. Amongst the most important subassemblies there are definitely coaxial cables that provide interconnections between experiment subsystems. It is commonly known that the major source of phase drifts in coaxial cables is their sensitivity to temperature changes. The phenomenon of phase drifts in cables is discussed in this paper. A phase drift measurement setup is described. Samples of cables of various types used in RF system installations have been measured. Measurement results are presented.
2
Content available remote

Investigation of New Algorithms for Estimation of Losses in Microwave Devices Based on a Waveguide or a Meander Line

100%
Plonis D., Katkevičius A., Mališauskas V., Serackis A., Matuzevičius D.
Acta Physica Polonica A
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2016
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vol. 129
|
issue 3
414-424
EN
The aim of this paper was to introduce the estimation of the losses in the prototypes of the microwave devices. We proposed in this paper two algorithms: an algorithm for evaluation of losses in the microwave devices based on a waveguide and an algorithm for evaluation of losses in the microwave devices based on a meander line. In order to verify the results of losses evaluation for the waveguide-based device, we have used the electrodynamic model of the open cylindrical gyrotropic waveguide with one anisotropic dielectric layer and the electrodynamic model of the open cylindrical gyrotropic waveguide with two dielectric layers. In order to verify the results of losses evaluation for the meander line-based device, we have used the model of the meander line with asymmetrical periodical inhomogeneity. The comparison of the losses evaluation results received by the algorithms proposed in this paper and the results received by application of the commercial software together with the alternative methods confirmed that the proposed algorithms produced correct results.
3
Content available remote

Semi-Automatic Analysis of Gyrotropic Semiconductor Waveguides Using Neural Network

63%
Plonis D., Malisauskas V., Serackis A.
Acta Physica Polonica A
|
2011
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vol. 119
|
issue 4
542-547
EN
This paper focuses on the analysis technique of gyrotropic circular cylindrical semiconductor waveguide by the use of an electrodynamical model. Authors propose the semi-automatic extraction of the dispersion characteristics by the use of single-layer perceptron neural network. The waveguide analysis algorithm consists of four main stages: initialization of system parameters, evaluation of transcendental linear dispersion equation system, extraction of dispersion characteristics and evaluation of the waveguide broad bandwidth. In this paper three types of waveguides (n-InP, n-InSb and p-InP) are analysed using a proposed algorithm. According to the results of analysis, the use of gyrotropic n-InP and p-InP semiconductor, semiconductor-dielectric waveguides are more preferred than to n-InSb waveguides due to their wider broad bandwidth.
4
Content available remote

Parametric Synthesis of Meander Slow-Wave System with Additional Shields

63%
Metlevskis E., Martavičius R., Katkevičius A., Plonis D., Krukonis A.
|
EN
The algorithm of parametric synthesis of meander slow-wave system with additional shields is presented in this paper. The influence of main constructive parameters of meander slow-wave system with additional shields on its electrical characteristics was evaluated in order to achieve the optimal results of the synthesis. Verification of the algorithm of parametric synthesis of meander slow-wave system with additional shields was carried out using four different models of meander slow-wave system with additional shields grounded in different positions. Sonnet® software package which is based on the method of moments has been used during the investigation.
5
Content available remote

TE Surface Waves in a Plasma Sandwich Structure

63%
Shaikh M., Zamir B., Ali R.
Acta Physica Polonica A
|
2015
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vol. 127
|
issue 6
1625-1629
EN
Transverse electric surface waves are analyzed in a plasma medium bounded by a left-handed material. A dispersion relation is obtained by applying the boundary conditions for the tangential field components. Numerical investigations show the dependence of effective wave index on the propagation frequency for different thicknesses and number densities of the plasma medium and also for different values of the filling factor of left-handed material.
6
Content available remote

Analysis of Charge Distribution on Rectangular Microstrip Structures

51%
Metlevskis E., Urbanavicius V.
Acta Physica Polonica A
|
2011
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vol. 119
|
issue 4
503-508
EN
Rectangular microstrip structures are widely used in various microwave devices. Using the method of moments and principle of partial images, various techniques are developed to determine charge distribution in 2D models of microstrip structures (their cross-section). In this paper, a technique for calculating surface charge distribution and total capacitance of complex 3D rectangular microstrip structures is proposed using the mentioned method and principle. To demonstrate feasibility of the proposed technique, five rectangular microstrip structures were investigated. Obtained results are compared with the data published by other researchers. Total error is typically in 6-12% range.
7
Content available remote

High Voltage Subnanosecond Monocycle Active Former Based on Compression Energy Unit

51%
Ulmaskulov M., Shunailov S., Sharypov K.
Acta Physica Polonica A
|
2009
|
vol. 115
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issue 6
1007-1009
EN
Compact high voltage subnanosecond monocycle former (MF) was tested. The device was designed on base of energy compression device and operated in a travelling wave mode. MF consists of high impedance and forming lines, which discharged for the load in parallel. As a result, the monocycle with pulse duration ∼1 ns and typical peak-to-peak amplitude ∼250 kV was formed without additional peaking of the nanosecond pulse rise time. Some pulses reached the maximum amplitude ∼270 kV. The parallel discharge circuit, and a spiral shape of forming line allowed keeping small dimensions of MF, and save enough electrical strength to operate with pulse repetition rate up to 100 pps.
8
Content available remote

Anomalous Phase and Attenuation Constants of SiC Rod Waveguide at Higher Temperatures

51%
Acta Physica Polonica A
|
2013
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vol. 123
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issue 1
58-61
EN
Here we present the dependences of the phase and attenuation constants of silicon carbide (SiC) cylindrical rod waveguide upon frequency at different temperatures, i.e. T = 1800C and T = 1900C when the rod radius is relatively large. We have also calculated the electric and magnetic field distributions at different frequencies in order to explain the anomalous attenuation. The SiC rod waveguide was investigated by the partial area method. The complex roots have been found by the Müller method. Computer codes for calculations were written in MATLAB language.
9
Content available remote

Wave Phenomena in High-Voltage Windings of Transformers

51%
Banaszak S., Gawrylczyk K.
Acta Physica Polonica A
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2014
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vol. 125
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issue 6
1335-1339
EN
Determination of mechanical condition of transformer active part can be performed utilizing frequency response of the windings. Many computing models were developed to evaluate behavior of the winding in wide frequency range using different numerical methods. Most of them utilizes finite elements, assuming axial symmetry, if possible. In other cases we need to use a three-dimensional model, which results in a significant reduction in the accuracy of modeling the geometry of the system, as well as the penetration of electromagnetic field into conductors. From a practical point of view, using computer of average performance, the windings can be modeled with at most 10 turns. From this reason mixed models are proposed, where the electric parameters of the winding are concentrated in the substitute RLC elements. Such models are known as "lumped parameter models". Since the parameters of real winding are distributed, the question arises concerning the necessity of taking into account wave phenomena in them. The method allowing this is known as "transmission line method". Measurements of frequency response are used in industry. There are still many problems with interpretation of test results. Computer modeling may be a helpful tool allowing to understand relation between the geometry of a winding and its frequency response. To fulfill this, models should give similar response as a real measurement. The paper describes a modified transmission line method used for modeling of a transformer winding's frequency response. There is described the model, its parameters, and exemplary solution compared to test data.
10
Content available remote

YIG Film for Magnetic Field Sensor

45%
Kaya A., Atalay S., Gencer H., Kaya O., Kolat V., Izgi T.
Acta Physica Polonica A
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2015
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vol. 127
|
issue 4
937-939
EN
Single crystal Y₃Fe₅O_{12} (YIG) film was grown onto (111) oriented gadolinium gallium garnet (GGG) substrate by the liquid phase epitaxy (PLD) technique. The X-ray diffraction measurements showed that epitaxial growth of the film along its (111) axis. The surface characteristic was investigated by atomic force microscopy (AFM) measurement. The magnetic field sensor consisted of a rectangular shape with 5 mm wide, 15 mm long and 5 μm thick YIG film and a pair of identical 50 μm wide microstrip copper transducers elements separated by 6 mm. The filter was tested by measuring reflection S_{11} characteristic at various bias magnetic fields. The results have showed that when the bias field increased from 0 to 2.5 kOe, the frequency value corresponding to S_{11} maxima increased from 1 GHz to 9 GHz. This suggests that the wide range magnetic field sensing and the highly sensitive field sensing are simultaneously fulfilled with the YIG film.
11
Publication available in full text mode
Content available

Aspects of the Scattering and Impedance Properties of Chaotic Microwave Cavities

38%
Hemmady S., Zheng X., Antonsen T., Ott E., Anlage S.
Acta Physica Polonica A
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2006
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vol. 109
|
issue 1
65-71
EN
We consider the statistics of the impedance Z of a chaotic microwave cavity coupled to a single port. We remove the non-universal effects of the coupling from the experimental Z data using the radiation impedance obtained directly from the experiments. We thus obtain the normalized impedance whose probability density function is predicted to be universal in that it depends only on the loss (quality factor) of the cavity. We find that impedance fluctuations decrease with increasing loss. The results apply to scattering measurements on any wave chaotic system.
12
Content available remote

Transverse magnetic scattering of two incident plane waves by a dielectric coated cylindrical reflector

32%
Mushref M.
Open Physics
|
2005
|
vol. 3
|
issue 2
229-246
EN
Scattering characteristics of two plane waves are investigated for a circular cylinder covered by a dielectric substance. Fields are assumed to be transverse magnetic (TM) and represented in an exponential series form. The diffracted radiations are found by applying the boundary conditions to the wave functions. The wave transformation method and the orthogonality of the exponential functions are respectively employed to obtain an infinite series in the solution. Numerical results are evaluated by reducing the infinite series to a finite number of terms and comparing estimates with the single plane wave scattering situation.
13
Content available remote

Numerical Analysis of Metal-Cylinder-Based Microwave Plasma Module

26%
Sobański M., Jasiński M., Mizeraczyk J.
Acta Physica Polonica A
|
2014
|
vol. 125
|
issue 6
1309-1312
EN
We present optimization of energy transfer in the waveguide-supplied metal-cylinder-based microwave plasma module with an inner cylindrical quartz tube. The construction of microwave plasma module is based on a WR 340 waveguide standard. Presented microwave plasma module operates at atmospheric pressure and frequency of 2.45 GHz. There is a reduced height section waveguide in microwave plasma module which provides local increase of the electric field in the plasma region. Microwave plasma module is terminated with a movable plunger which plays the role of the tuning element. Tuning characteristics of microwave plasma module are defined as the dependence of the P_{R}/P_{I} on the position l_{s} of the movable plunger, where P_{R} and P_{I} are the microwave power reflected and power incident, respectively. The powers P_{R} and P_{I} are measured in the input plane of microwave plasma module. The purpose of the presented optimization is to achieve P_{R} lower than 5% of P_{I} in widest range of position of movable plunger l_{s}. We used Comsol Multiphysics software to make numerical analysis which allows to optimize the parameters of microwave plasma module. Results of numerical analysis show that P_{R}/P_{I} is lower than 0.05 in a wide range of movable plunger position l_{s}.
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