circular polarizations

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A Dual-Band CPW-Fed L-Slot Antenna with Both Linear and Circular Polarizations

A Dual-Band CPW-Fed L-Slot Antenna with Both Linear and Circular Polarizations

In this paper, the bandwidth enhancement and CP operation of the CPW-fed L-slot antenna have been successfully demonstrated. Two orthogonal resonant paths of the microstrip L-slot antenna were excited simultaneously through a CPW line, thus causing the CP excitation. By carefully tuning the dimension of the ground plane, the band and performance of CP can be improved in additional to size reduction. After the input impedance was studied with respect to those dimensions, a printed CP antenna with good impedance match was successfully constructed by introducing a protruded stub at the feedline. With the good performance of the dual bands and both linear and circular polarizations, the proposed CPW-fed slot antenna is suitable for use as the radiated element in many systems of mobile communication, such as DCS (1710 ∼ 1880 MHz), PCS (1850 ∼ 1990 MHz), WCDMA (1920 ∼ 2170 MHz), SDAR (2332 ∼ 2345 MHz), WLANs (2400 ∼ 2483.5 MHz, 5150 ∼ 5850 MHz), LTE (2500–2690 MHz) and Hiper-LAN (5150 ∼ 5350 MHz), etc..
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A Compact Size and Small Frequency Ratio CPW-Fed Circular Slot Antenna for GPS/WLAN Dual-Band and Circular Polarizations

A Compact Size and Small Frequency Ratio CPW-Fed Circular Slot Antenna for GPS/WLAN Dual-Band and Circular Polarizations

Based on the techniques of circular slot antenna [5], loaded spiral slots in the ground plane [7], crane-shaped strip in the ground plane [8] and the GPS and WLAN functionalities [9], the improved CPW-fed circular slot antenna embedded with two open-ground rings is designed for achieving dual-band and circular polarizations in this paper. The proposed circular slot antenna consists of two opened-ground rings and the enhanced feed strip of CPW. The two opened-ground rings facing in opposite directions can result in different senses of circular polarization. The dual-band operation is achieved by using the enhanced feed strip. Both simulated and experimental results show the performance of the proposed antenna. It is a simply structure and available CPW-fed slot antenna for GPS and WLAN systems.
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A Novel Design of Dual-Band Circularly Polarized Antenna Based on Patches Having Rotation Angles

A Novel Design of Dual-Band Circularly Polarized Antenna Based on Patches Having Rotation Angles

A dual-band CP patch antenna with LHCP in the lower band and RHCP in the higher band is presented in this paper. Different from other antennas with complex structure and narrow impedance and circular polarization bandwidth, the dual-band circular polarizations based on aperture coupled feed are achieved by adopting two rotated rectangular patches with different angles. The measured 10-dB impedance bandwidths and 3 dB AR bandwidths are 18.4% and 3.21% in the lower band and 12.4% and 1.7% in the higher band, respectively. Due to its simple structure, compact size and excellent performance, the antenna is expected to be applied to wireless communications.
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DESIGNER POLARIZATION

DESIGNER POLARIZATION

All polarizations fall into the general category of elliptical polarization, the general case of which linear and circular polarizations are limiting cases. Figure 4 below shows the relationship between the amplitude and phase of the power fed to the two sinuous inputs and the polarization of the approaching wave. The mathematics of the polarization shown in Figure 4 is included in the Appendix at the end of this document. For the cases of ± ∞ dB, we have the limiting case of linear vertical and horizontal polarizations. For the case of 0 dB and ±90°, we have left and right hand circular polarizations. Slant polarizations result for the in and out of phase conditions of 0° and 180°.
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Polarization singularities in isotropic random vector waves

Polarization singularities in isotropic random vector waves

We have studied the C and L lines identi­ ed (Nye & Hajnal 1987) as the singularities of complex vector waves, that is, singularities of ­ elds of polarization ellipses. But the following naive argument leads to the fallacious conclusion that the L singularities would be surfaces rather than lines. On the Poincar´e sphere (Born & Wolf 1959) that represents polarization, the two circular polarizations correspond to two points (the poles), while the linear polarizations correspond to a line (the equator), so C singularities would have codimension two, corresponding to lines in space, and L singularities would have codimension one, corresponding to surfaces in space.
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Polarizations as States and Their Evolution in Geometric Algebra Terms with Variable Complex Plane

Polarizations as States and Their Evolution in Geometric Algebra Terms with Variable Complex Plane

Recently suggested scheme [1] of quantum computing uses g-qubit states as circular polarizations from the solution of Maxwell equations in terms of geometric algebra, along with clear definition of a complex plane as bivector in three dimensions. Here all the details of receiving the solution, and its pola- rization transformations are analyzed. The results can particularly be applied to the problems of quantum computing and quantum cryptography. The sug- gested formalism replaces conventional quantum mechanics states as objects constructed in complex vector Hilbert space framework by geometrically feasible framework of multivectors.
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A Novel Miniaturized Frequency Selective Surface with Very Stable Performance

A Novel Miniaturized Frequency Selective Surface with Very Stable Performance

For this paper, a miniaturized frequency selective surface (MFSS) with excellent stability towards incident angles and polarizations is presented. The metallic SIE structures are set on one side of the dielectric layer, with an additional metalized patch array on the other side. The advantage of the proposed structure lies in its higher miniaturization level, better stability and lower cost. The

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Casimir Interactions Between Scatterers in Carbon Nanotubes

Casimir Interactions Between Scatterers in Carbon Nanotubes

In this thesis we calculate interactions between localized scatterers in metallic carbon nanotubes. Backscattering of electrons between localized scatterers mediates long range forces between them. These interactions are mapped to Casimir forces mediated by one-dimensional massless fermions and calculated using a force operator approach. We first study interactions between scatterers described by spinor polarized potentials relevant to the single-valley problem in carbon nanotubes. We obtain the force between two finite width square barriers, and take the limit of zero width and infinite potential strength to study the Casimir force mediated by the fermions. For the case of identical scatterers we recover the conventional attractive one dimensional Casimir force. For the general problem with inequivalent scatterers we find that the magnitude and sign of this force depend on the relative spinor polarizations of the two scattering potentials which can be tuned to give an attractive, a repulsive, or a compensated null Casimir interaction.
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Solanum Chemosystematic Aspects: Analysis of Mixed Pathway (Acetate/Shikimate) Special Metabolites

Solanum Chemosystematic Aspects: Analysis of Mixed Pathway (Acetate/Shikimate) Special Metabolites

Abstract Solanum L. is a large, diverse and important Solanaceae genus, which taxonomy and infrageneric relationships are still unresolved, as well as its evolutionary history. Biosynthesized from the mixed pathway (acetate/shikimate) and considered good systematic markers, flavonoids are widely distributed among plant species, as also in Solanum. Through analysis of flavonoid chemical data, this work aims to study evolutionary polarizations and contribute towards the comprehension of species phylogenetic relationships in the genus. The chemosystematic analysis was conducted through calculation of flavonoids chemical parameters and employing multivariate statistical analysis (factor analysis). Chemical data survey led to the identification of 479 metabolites from the mixed pathway. The results obtained demonstrate Solanum species prefer to biosynthesize hydroxylflavonoids. However, when oxy-groups are protected, choose O-glycosylflavonoids rather than O-methylflavonoids. The chemometric analysis showed derivation of eight Leptostemonum species, clearly separated from the rest of Solanum due to O-methylation. This feature suggests a possible advancement of Leptostemonum species. At last, considering this preliminary analysis, it was possible to identify remarkable trends in flavonoid evolution in Solanum species.
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Measurement of the Y(nS) polarizations in pp collisions at s=7 and 8 TeV

Measurement of the Y(nS) polarizations in pp collisions at s=7 and 8 TeV

Physikalisches Institut, RWTH Aachen University, Aachen, Germany Fakult¨ at Physik, Technische Universit¨ at Dortmund, Dortmund, Germany Max-Planck-Institut f¨ ur Kernphysik MPIK, Heidel[r]

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Low-Profile Omnidirectional Antenna with Dual Polarizations for 2.4 GHz
 WLAN Applications

Low-Profile Omnidirectional Antenna with Dual Polarizations for 2.4 GHz WLAN Applications

Abstract—A low-profile antenna is proposed in this letter for realizing dual polarizations with omnidirectional radiation patterns. Vertical polarization is obtained by a modified annular ring slot antenna, and horizontal polarization is obtained by a modified printed arc dipole array. By combining the ground plane of the ring slot antenna and the dipole array on the same layer, the profile of the antenna is reduced to minimum extent. The proposed prototype has a low profile of 0 . 024 λ ( λ is the free- space wavelength at 2.4 GHz). To verify the design, the proposed antenna is fabricated and measured. Measured reflection coefficients, isolation, and radiation patterns data agree well with the simulated results. The common band of vertical and horizontal polarizations makes the proposed antenna satisfy the WLAN diversity systems with omnidirectional characteristic.
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Materials Insertion Loss at 2.4, 3.3 and 5.5 GHz
 Bands

Materials Insertion Loss at 2.4, 3.3 and 5.5 GHz Bands

Figure 3 shows the propagation loss at the nine points of measurements for the horizontal and vertical polarizations. For the horizontal polarization, it can be noticed that the minimum [r]

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Chiral Imbalance in QCD and its consequences

Chiral Imbalance in QCD and its consequences

quarks. In short, the chirality imbalance is a direct manifestation of the QCD topological fluctuations and could become observable through the asymmetry in polarizations of dilepton pairs [13] in central heavy ion collisions (HIC) and the Chiral magnetic wave (CMW) in non-central HIC [14]. Summa- rizing one can say that the Chiral imbalance (ChI) of quarks is a remarkable phenomenon that stems from highly nontrivial interplay of chiral symmetry of QCD, axial anomaly, and the topology of gluon configurations.

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Stokes parameters in the unfolding of an optical vortex through a birefringent crystal

Stokes parameters in the unfolding of an optical vortex through a birefringent crystal

Abstract: Following our earlier work (F. Flossmann et al., Phys. Rev. Lett. 95 253901 (2005)), we describe the fine polarization structure of a beam containing optical vortices propagating through a birefringent crystal, both experimentally and theoretically. We emphasize here the zero surfaces of the Stokes parameters in three-dimensional space, two transverse dimensions and the third corresponding to optical path length in the crystal. We find that the complicated network of polarization singularities reported earlier – lines of circular polarization (C lines) and surfaces of linear polarization (L surfaces) – can be understood naturally in terms of the zeros of the Stokes parameters.
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Analysis and Computation using GTD of a conducting Surface of Paraboloid Reflectors

Analysis and Computation using GTD of a conducting Surface of Paraboloid Reflectors

It is interesting that even though the polarizations and the wavefront curvatures of the incident, reflected, and diffracted waves are markedly different, the total field calculated from this high-frequency solution for the curved wedge is continuous at shadow and reflection boundaries. Representative numerical results illustrating the application of the method and the properties of the offset paraboloid are present. Results obtained from the above assumptions would only be good for small f/D ratios and small beam width scans. New formulations for the offset geometry are an important subject for future study. For the sake of completeness we have used our general purpose computer program and generated most of the results reported in [10]. Our results compared very favorably with those given in [10], and in most cases considerably less computer time was needed in comparison with other techniques.
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Non-parametric methods for circular-circular and circular-linear

Non-parametric methods for circular-circular and circular-linear

The two buoys have been chosen such that the distance between them is relatively small (33.35 nautical miles/61.77 km) and they share several features, such as similar distance to land. The data have been cleaned to erase any missing values and after this, the data set contained 24807 observations. Figure 1 shows circular Bernstein polynomial fits of the marginal densities of the wind directions at the two buoys. It can be seen that, as we might expect, the distribution of wind directions at the two sites are very similar.

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Wideband Dual-Polarized Crossed-Dipole Antenna with Parasitical Crossed-Strip for Base Station Applications

Wideband Dual-Polarized Crossed-Dipole Antenna with Parasitical Crossed-Strip for Base Station Applications

The wideband dual-polarized crossed-dipole antenna with the parasitical crossed-strip is presented and investigated. Using the parasitical crossed-strip to achieve another resonate point and effectively improve the impendence bandwidth and the isolation between the two orthogonal polarizations of the upper band, the proposed antenna can achieve a wideband operating impendence characteristics about 34.9% for S 11 ≤ −10 dB (+45 ◦ polarization) and S 22 ≤ −10 dB (−45 ◦ polarization) and high isolation

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Design & Analysis of a Modified Circular Microstrip Patch Antenna with Circular Polarization and Harmonic Suppression

Design & Analysis of a Modified Circular Microstrip Patch Antenna with Circular Polarization and Harmonic Suppression

Active Integrated Antennas and rectifying antennas (rectenna) applications in millimeter wave range are getting much attention in recent years especially in the field of power combining, beam steering and switching, and high efficiency power amplifiers. Rectennas were earlier proposed for high power transmission [3]. Nowadays application of rectennas in low power RFID tags, proximity cards, and contactless smart cards is well known. These applications lies within the allowed electromagnetic radiation power levels. Distance between electromagnetic source and antenna is within 5cms [4]. Using a passive RFID tag makes the system more cost effective as the need for power supply to the tags will be eliminated by using rectenna. Proximity cards and contactless smart cards have become quite popular in ticketing and easy money payment systems. Delhi metro uses [5] cards which are rectenna based cards and which can be used without even removing the card from wallet or bag. In this paper a circular microstrip patch antenna with embedded circular slots to obtain harmonic suppression and peripheral cuts for producing circular polarization (CP) is proposed and discussed.
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Broadband dipole antenna for DOA systems applications

Broadband dipole antenna for DOA systems applications

The design of Microstrip antennas with circular polarization and wide bandwidth axial ratio is complex in most cases, in this sense, a circular patch design with circular polarization and reconfigurable sense of rotation is presented in [6] achieving 27.39% impedance bandwidth for a reflection coefficient magnitude 𝑆11 < −10𝑑𝐵 in the range from 2.295 𝐺𝐻𝑧 to 3.025 𝐺𝐻𝑧 , a maximum gain of 6.04 𝑑𝐵𝑖 and a 13% axial ratio bandwidth for -3dB reference. Moreover, a design with circular ring geometry short-circuited and reconfigurable sense of rotation is presented in [7] where a 33.33% impedance bandwidth in 1.9𝐺𝐻𝑧 - 2.66𝐺𝐻𝑧 frequency range for a reflection coefficient less than -10 dB was achieved, a
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Investigation Parametric Model of Friction Stir Welding

Investigation Parametric Model of Friction Stir Welding

Import rectangular base plate first into assembly window then select default option this default option makes object planes coincide with assembly planes. Then import other plate also and place it contact with other plate. Here we are using only coincide constraint option for all these constraints. And then import circular tool and place at middle of the plates and we created complete assembly model by using only constraint option only.

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