Neurospectral modeling of rectangular patch with rectangular aperture in the ground plane

2014 ◽  
Vol 7 (6) ◽  
pp. 759-768 ◽  
Author(s):  
Lotfi Djouane ◽  
Sami Bedra ◽  
Randa Bedra ◽  
Tarek Fortaki
Keyword(s):  
Ground Plane ◽  
Accurate Determination ◽  
Rectangular Aperture ◽  
Rectangular Patch ◽  
Spectral Domain Approach ◽  
Performances Evaluation ◽  
Half Power ◽  
Theoretical Results ◽  
Good Agreement

In this study, we propose an artificial neural network in conjunction with spectral domain approach (SDA), for fast and accurate determination of the resonant frequency and half-power bandwidth of rectangular patch over the ground plane with rectangular aperture. The performances evaluation of the neurospectral method reveals superiority over the conventional SDA model in terms of errors and time. The results obtained from the neurospectral method are in very good agreement with the experimental and theoretical results available in the literature. Finally, numerical results for the effect of rectangular aperture dimensions on the resonant characteristics of the rectangular patch are also investigated.

scholarly journals Triangular Slot-Loaded Wideband Planar Rectangular Antenna Array for Millimeter-Wave 5G Applications

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 778
Author(s):  
Iftikhar Ahmad ◽  
Houjun Sun ◽  
Umair Rafique ◽  
Zhang Yi
Keyword(s):  
Antenna Array ◽  
Millimeter Wave ◽  
Communication Systems ◽  
Ground Plane ◽  
Simulated Data ◽  
Impedance Bandwidth ◽  
Antenna Element ◽  
Single Antenna ◽  
Rectangular Patch ◽  
Half Power

This paper presents a design of a triangular slot-loaded planar rectangular antenna array for wideband millimeter-wave (mm-wave) 5G communication systems. The proposed array realizes an overall size of 35.5 × 14.85 mm2. To excite the array elements, a four-way broadband corporate feeding network was designed and analyzed. The proposed array offered a measured impedance bandwidth in two different frequency ranges, i.e., from 23 to 24.6 GHz and from 26 to 45 GHz. The single-antenna element of the array consists of a rectangular patch radiator with a triangular slot. The partial ground plane was used at the bottom side of the substrate to obtain a wide impedance bandwidth. The peak gain in the proposed array is ≈12 dBi with a radiation efficiency of >90%. Furthermore, the array gives a half-power beamwidth (HPBW) of as low as 12.5°. The proposed array has been fabricated and measured, and it has been observed that the measured results are in agreement with the simulated data.

scholarly journals Low Cross-Polarization Improved-Gain Rectangular Patch Antenna

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1189 ◽  
Author(s):  
Anurag Singh ◽  
Sandip Vijay ◽  
Rudra Narayan Baral
Keyword(s):  
Patch Antenna ◽  
Frequency Selective Surface ◽  
Cross Polarization ◽  
Gain Enhancement ◽  
Rectangular Patch ◽  
Shorting Pin ◽  
Half Power ◽  
Broadside Radiation ◽  
Polarization Level ◽  
Good Agreement

In this paper, a low cross-polarization improved-gain rectangular patch antenna is presented. A patch-ground shorting pin with defected patch structure (DPS) is introduced to suppress the cross-polarization level. A High Reflective Frequency Selective Surface (HRFSS) superstrate is designed and placed over the proposed antenna at an optimized position to intensify the gain. To characterize the unit-cell of the superstrate, its transmission characteristics are extracted and discussed. Integration of the superstrate achieves a beam contraction resulting in a gain enhancement to 10.65 dBi. The proposed antenna has perfect broadside radiation with a cross-polarization level of below −30 dB in the entire half power beamwidth. The prototype of the antenna exhibits good agreement between experimental and simulated results.

The Proton Magnetic Resonance Spectra of some Chlorinated Polycyclodiene Pesticide Metabolites. Rapid Assessment of Stereochemistry

1971 ◽  
Vol 49 (12) ◽  
pp. 1993-2003 ◽  
Author(s):  
J. D. McKinney ◽  
L. H. Keith ◽  
A. Alford ◽  
C. E. Fletcher
Keyword(s):  
Magnetic Resonance ◽  
Accurate Determination ◽  
Rapid Assessment ◽  
Shift Reagent ◽  
Coupling Constant ◽  
Pesticide Metabolites ◽  
Relative Stereochemistry ◽  
Superimposed Signals ◽  
Good Agreement

The rapid and accurate determination of the relative stereochemistry of some postulated chlorinated polycyclodiene pesticide metabolites without excessive dependence on chemical methods is described. Proton assignments were made employing the new nuclear magnetic resonance (n.m.r.) shift reagent, Eu(DPM)3, which effected the separation of superimposed signals in these systems. The assignments based on coupling constant information and requiring spin decoupling equipment are in good agreement with those obtained from the Eu(DPM)3 studies. The data presented establishes the relative stereochemistry of these biologically important compounds and demonstrates the utility of one or both approaches in elucidating their overall structures.

Determination of the flexural stiffness of thin plates from small deflection measurements using optical holography

1982 ◽  
Vol 17 (1) ◽  
pp. 53-61 ◽  
Author(s):  
M J Marchant ◽  
M B Snell
Keyword(s):  
Numerical Method ◽  
Accurate Determination ◽  
Metal Plate ◽  
Thin Plates ◽  
Flexural Stiffness ◽  
Interference Fringes ◽  
Small Deflection ◽  
Stiffness Properties ◽  
Good Agreement

A technique is presented for accurate determination of the flexural stiffness of thin plates using optical holography. Measurements of the interference fringes on thin rhombic plates in anticlastic bending are used to calculate the components of curvature by a simple numerical method Control experiments on a metal plate give good agreement with the results of small deflection bending theory. The method appears ideally suited to the measurement of anisotropic flexural stiffness properties.

scholarly journals Theory determination of $$\varvec{\bar{B}\rightarrow D^{(*)}\ell ^-\bar{\nu }}$$ form factors at $$\varvec{\mathcal {O}(1/m_c^2)}$$

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Marzia Bordone ◽  
Martin Jung ◽  
Danny van Dyk
Keyword(s):  
Experimental Data ◽  
Light Cone ◽  
Sum Rules ◽  
Form Factors ◽  
Longitudinal Polarization ◽  
Polarization Fraction ◽  
Theoretical Results ◽  
Good Agreement ◽  
Lepton Flavour

Abstract We carry out an analysis of the full set of ten $$\bar{B}\rightarrow D^{(*)}$$B¯→D(∗) form factors within the framework of the Heavy-Quark Expansion (HQE) to order $$\mathcal {O}\left( \alpha _s,\,1/m_b,\,1/m_c^2\right) $$Oαs,1/mb,1/mc2, both with and without the use of experimental data. This becomes possible due to a recent calculation of these form factors at and beyond the maximal physical recoil using QCD light-cone sum rules, in combination with constraints from lattice QCD, QCD three-point sum rules and unitarity. We find good agreement amongst the various theoretical results, as well as between the theoretical results and the kinematical distributions in $$\bar{B}\rightarrow D^{(*)}\lbrace e^-,\mu ^-\rbrace \bar{\nu }$$B¯→D(∗){e-,μ-}ν¯ measurements. The coefficients entering at the $$1/m_c^2$$1/mc2 level are found to be of $$\mathcal {O}(1)$$O(1), indicating convergence of the HQE. The phenomenological implications of our study include an updated exclusive determination of $$|V_{cb}|$$|Vcb| in the HQE, which is compatible with both the exclusive determination using the BGL parametrization and with the inclusive determination. We also revisit predictions for the lepton-flavour universality ratios $$R_{D^{(*)}}$$RD(∗), the $$\tau $$τ polarization observables $$P_\tau ^{D^{(*)}}$$PτD(∗), and the longitudinal polarization fraction $$F_L$$FL. Posterior samples for the HQE parameters are provided as ancillary files, allowing for their use in subsequent studies.

scholarly journals Corrections to the Hipparcos proper motions in declination for 807 stars

2008 ◽  
pp. 109-113 ◽  
Author(s):  
G. Damljanovic ◽  
N. Pejovic
Keyword(s):  
Accurate Determination ◽  
Annual Number ◽  
Time Interval ◽  
Proper Motions ◽  
Hipparcos Catalogue ◽  
Time Variations ◽  
Better Than ◽  
Good Agreement

We used the data on latitude variations obtained from observations with 10 classical photographic zenith tubes (PZT) in order to improve the Hipparcos proper motions in declinations ?? for 807 stars. Part of observing programmes, carried out during the last century for the purpose of studying the Earth's rotation, were realized by using PZT instruments. These observations were performed within in the intervals (tens of years) much longer than that of the Hipparcos mission (less than 4 years). In addition, the annual number of observations for every PZT programme star is several hundreds on the average. Though the accuracy of the star coordinates in the Hipparcos Catalogue is by two orders of magnitude better than that of the star coordinates from the PZT observations, the large number of observations performed a much longer time interval makes it possible to correct the Hipparcos proper motions and to improve their accuracy with respect to the accuracy given in the Hipparcos Catalogue. Long term examinations of latitude and time variations were used to form the Earth Orientation Catalogue (EOC-2), aimed at a more accurate determination of positions and proper motions for the stars included. Our method of calculating the corrections of the proper motions in declination from the latitude variations is different from the method used in obtaining the EOC-2 Catalogue. Comparing the results we have established a good agreement between our ?? and the EOC-2 ones for the star sample used in the present paper.

Laminar Free Convection From a Downward-Projecting Fin

1968 ◽  
Vol 90 (1) ◽  
pp. 63-70 ◽  
Author(s):  
G. S. H. Lock ◽  
J. C. Gunn
Keyword(s):  
Boundary Layer ◽  
Free Convection ◽  
Prandtl Number ◽  
Experimental Program ◽  
Boundary Layer Problem ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement ◽  
Quiescent Fluid

A theoretical analysis of conduction through and free convection from a tapered, downward-projecting fin immersed in an isothermal quiescent fluid is presented. The problem is solved by assuming quasi-one-dimensional heat conduction in the fin and matching the solution to that of the convection system, which is treated as a boundary layer problem. For an infinite Prandtl number, solutions are derived which take the form of a power law temperature distribution along the fin. The effect of this power (n) on heat transfer, drag, and the corresponding boundary layer profiles is discussed. It is shown that n is independent of the fin profile and dependent on a single nondimensional group χ. The theoretical results for infinite Prandtl number are compared with corresponding results derived from previous work using a Prandtl number of unity. The effect of Prandtl number on the determination of n and consequently the fin effectiveness is found to be extremely small. The results of an experimental program are also presented. These consist of temperature profiles and the n — χ relation for different fin geometries and surrounding fluids. Comparison with the theoretical predictions reveals good agreement.

scholarly journals Determination of effective atomic numbers and electron densities from mass attenuation coefficients for some selected complexes containing lanthanides

2017 ◽  
Vol 95 (10) ◽  
pp. 1005-1011 ◽  
Author(s):  
Ferdi Akman ◽  
Mustafa Recep Kaçal ◽  
Feride Akman ◽  
Mustafa Serkan Soylu
Keyword(s):  
Chemical Parameters ◽  
Electron Densities ◽  
Attenuation Coefficients ◽  
Transmission Geometry ◽  
Mass Attenuation Coefficients ◽  
Effective Atomic Numbers ◽  
Theoretical Results ◽  
Good Agreement ◽  
Mass Attenuation

The effective atomic numbers and electron densities for the pure elemental forms of gadolinium (Gd), dysprosium (Dy), erbium (Er), and ytterbium (Yb), and some of their selected complexes, were obtained from the measured total mass attenuation coefficients at 13.92, 17.75, 20.78, 26.34, and 59.54 keV photon energies using a high-resolution Si(Li) detector by adopting transmission geometry. The measured results were compared with two different theoretical results. Within experimental deviations, our data are in good agreement with the theoretical values. The obtained parameters were also interpreted with some selected chemical parameters.

scholarly journals Determination of flavonoids and total polyphenol contents in commercial apple juices

2018 ◽  
Vol 36 (No. 3) ◽  
pp. 233-238 ◽  
Author(s):  
Leposava Pavun ◽  
Predrag Đurđević ◽  
Milena Jelikić-Stankov ◽  
Daniela Đikanović ◽  
Snežana Uskoković-Marković
Keyword(s):  
Fruit Juice ◽  
Accurate Determination ◽  
Flavonoid Content ◽  
Dpph Assay ◽  
Total Polyphenol ◽  
Strong Emission ◽  
Spectrofluorimetric Method ◽  
Good Agreement ◽  
Antioxidative Ability

We propose a sensitive and selective spectrofluorimetric method for the determination of flavonoids as expressed in ‘quercetin equivalent’ in apple juices. The method is based on the strong emission of the aluminium(III)-quercetin complex at 480 nm with excitation at 420 nm, and it is successfully applied for the determination of flavonoids in commercial apple juices and compared with results obtained in reference spectrophotometric determination. The flavonoid content in commercial apple juices was found to range from 5.53 to 15.55 mg/l quercetin equivalent. The very good agreement between the two methods indicates the suitability of the proposed spectrofluorimetric method for the precise and accurate determination of flavonoids. In addition, the total polyphenol content was determined spectrophotometrically using the Folin-Ciocalteu (FC) method and the antioxidative activity of the tested juices was tested in a DPPH assay and these values were correlated with each other. The obtained profiles of compounds with antioxidative ability lead us to conclude that fruit juice labels based only on fruit % might sometimes misinform consumers.

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