scholarly journals Hybrid Types of Waves Propagating in Double Ridged Waveguide with Piecewise-Layer Dielectric Filling

2018 ◽  
pp. 60-69
Author(s):  
A. V. Donchenko ◽  
G. F. Zargano ◽  
V. V. Zemlyakov
Keyword(s):  
Numerical Approach ◽  
Front View ◽  
Dielectric Substrates ◽  
Dielectric Sample ◽  
Layered Dielectric ◽  
Hybrid Waves ◽  
Ridged Waveguide ◽  
Top View ◽  
Dielectric Filling

The algorithm for calculating electrodynamic characteristics of hybrid types of waves propagating in double ridged waveguide with piecewise-layered dielectric filling is presented. The double ridged waveguide structure with dielectric plates installed between the ridges, and with dielectric sample sandwiched between the dielectric substrates is consid-ered. The calculations are carried out using the method of partial regions. The presented algorithm takes into account the electromagnetic field components singularities near the dielectric and metal edges of the waveguide. The technique for calculating the electromagnetic energy losses in the double ridged waveguide with a piecewise layered dielectric filling is provided. The classification of hybrid waves is given. The spatial structures of electromagnetic fields and their planar projections (front view, top view, side view) for the first two HEwaves and the first EH-wave are demonstrated. Cutoff fre-quencies and propagation constants of HEand EH-waves are calculated. The results obtained using the described meth-od and numerical approach are compared. Then the results are analyzed.

scholarly journals A theoretical and numerical approach for selecting miniaturized antenna topologies on magneto-dielectric substrates

2015 ◽  
Vol 7 (3-4) ◽  
pp. 369-377 ◽  
Author(s):  
Alex Pacini ◽  
Alessandra Costanzo ◽  
Diego Masotti
Keyword(s):  
Near Field ◽  
Dielectric Materials ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Microwave Range ◽  
Dielectric Substrates ◽  
Full Wave ◽  
Miniaturized Antenna ◽  
Wavelength Radiation ◽  
Definition Of

An increasing interest is arising in developing miniaturized antennas in the microwave range. However, even when the adopted antennas dimensions are small compared with the wavelength, radiation performances have to be preserved to keep the system-operating conditions. For this purpose, magneto-dielectric materials are currently exploited as promising substrates, which allows us to reduce antenna dimensions by exploiting both relative permittivity and permeability. In this paper, we address generic antennas in resonant conditions and we develop a general theoretical approach, not based on simplified equivalent models, to establish topologies most suitable for exploiting high permeability and/or high-permittivity substrates, for miniaturization purposes. A novel definition of the region pertaining to the antenna near-field and of the associated field strength is proposed. It is then showed that radiation efficiency and bandwidth can be preserved only by a selected combinations of antenna topologies and substrate characteristics. Indeed, by the proposed independent approach, we confirm that non-dispersive magneto-dielectric materials with relative permeability greater than unit, can be efficiently adopted only by antennas that are mainly represented by equivalent magnetic sources. Conversely, if equivalent electric sources are involved, the antenna performances are significantly degraded. The theoretical results are validated by full-wave numerical simulations of reference topologies.

Electrodynamic analysis of electromagnetic fields of hybrid waves propagating in the single-ridged waveguide

2017 ◽  
Vol 32 (6) ◽  
pp. 739-749 ◽  
Author(s):  
Alexey Vitalievich Donchenko ◽  
Gennadiy Philippovich Zargano ◽  
Viacheslav Viktorovich Zemlyakov
Keyword(s):  
Electromagnetic Fields ◽  
Electrodynamic Analysis ◽  
Hybrid Waves ◽  
Ridged Waveguide

Prediction methods for coning process

2021 ◽  
pp. 18-25
Author(s):  
E.F. Veliyev ◽  
Keyword(s):  
Computer Modeling ◽  
Analytical Approach ◽  
Laboratory Experiments ◽  
Numerical Approach ◽  
Prediction Methods ◽  
Field Development ◽  
The Third ◽  
Modern Methods ◽  
Definition Of

Currently, the percentage of the mature fields steadily rise and the process of formation of water and gas cones becomes unavoidable. The prediction of this process is essential for successful field development. Correlation dependencies developed for this purpose can be divided into three main groups. The models in the first group are based on the analytical approach of definition of balance conditions for viscous and gravitational powers in the reservoir. The methods in the second group are based on empiric approach, i.e. on the data obtained as a result of laboratory experiments or computer modeling. The methods in the third group are based on numerical approach. The paper presents the analysis and classification of modern methods for prediction of coning process.

scholarly journals Palynological characterization and genetic divergence between accessions of chilli and sweet peppers

2013 ◽  
Vol 31 (4) ◽  
pp. 568-573 ◽  
Author(s):  
Kellen C Martins ◽  
Sérgio Alessandro M Souza ◽  
Telma Nair S Pereira ◽  
Rosana Rodrigues ◽  
Messias G Pereira ◽  
...  
Keyword(s):  
Genetic Divergence ◽  
Pollen Grains ◽  
Principal Component ◽  
Polar View ◽  
Polar Axis ◽  
Area Index ◽  
Front View ◽  
Capsicum Spp ◽  
Polar Area

This study characterised pollen grains morphologically and studied the genetic divergence between accessions based on morphopollinic characters. Seven accessions, including domesticated, semi-domesticated and wild species of Capsicum (C. annuum var. annuum, C. chinense, C. baccatum var. pendulum, C. frutescens, Capsicum annuum var. glabriusculum, C. baccatum var. baccatum and C. parvifolium), were cultivated in a greenhouse and their pollen grains collected and fixed during flowering. The pollen grains were acetolysed and described based on 13 pollinic characteristics (polar and equatorial axes, in an equatorial front view; ratio between polar axis and equatorial axis; equatorial axis in a polar view; thicknesses of the exine, sexine and nexine; apocolpus side; polar area index; length and diameter of the pore and colpus). The genetic divergence analysis between the accessions was based on the standardised average Euclidean distance, and the grouping analysis was based on Ward's method. PCA (principal component analysis) is another multivariate method that was used. Based on Ward's method and PCA, it was possible to group the accessions into two groups, and the groups formed correlated with the classification of the gene pool complexes already described for the genus. According to this classification, the Capsicum genus comprises three major groups: C. annuum, C. chinense and C. frutescens form the annuum complex; C. baccatum and C. pratermissum form the baccatum complex; and C. eximium, C. cardenasii and C. pubescens form the pubescens complex. The variable width of the pores was the most discriminating in this morphopollinic study of Capsicum spp.

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