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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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 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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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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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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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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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

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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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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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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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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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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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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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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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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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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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

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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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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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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