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Circular polarization

About: Circular polarization is a research topic. Over the lifetime, 15201 publications have been published within this topic receiving 234418 citations.


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TL;DR: In this article, a study of the properties of the slot arms of a rectangular waveguide was conducted with the aim of obtaining information useful in design of a circularly polarized linear array.
Abstract: A pair of narrow slots crossed at right angles and located at the proper point in the broad wall of a rectangular waveguide will radiate a circularly polarized wave. Some of the results of a study of the properties of such slots is presented. The study was undertaken with the aim of obtaining information useful in design of a circularly polarized linear array. Some of the properties of the slot pairs are as follows: 1) They are inherently matched, independent of the slot length. 2) When the slot arms are made resonant, approximately 75 per cent of the incident power is radiated, with a vswr of 1.12. 3) When fed from one end of the waveguide, the slots radiate right-hand circular polarization; from the other end, left-hand. In using these slots in linear arrays the power radiated is varied by changing slot length, since position and orientation are fixed by the requirements of circular polarization. The slots must be separated by a guide wavelength, so waveguide loading or other complicated schemes must be used to reduce the slot spacing.

83 citations

Journal ArticleDOI
TL;DR: In this article, a monofilar spiral antenna is analyzed in the presence of a conducting plane reflector, using the method of moments, and a tilted beam of circular polarization is realized by superposing the fields from two active regions.
Abstract: A monofilar spiral antenna is analyzed in the presence of a conducting plane reflector, using the method of moments. The circumference of the spiral antenna is chosen to be 2.3 wavelengths. A tilted beam of circular polarization is realized by superposing the fields from two active regions. The gain of the tilted beam is approximately 8 dB. The frequency bandwidths for 1-dB gain drop and 3-dB axial ratio criterions are 12% and 23%, respectively. An array consisting of the four monofilar spiral antennas is also analyzed, where the array element spacing is chosen to be 0.8 wavelength at a design frequency f/sub 0/. The input impedances of the four spirals are almost the same as the impedance of the single monofilar spiral antenna at f/sub 0/. The array radiates a tilted fan beam with a gain increase of approximately 6 dB from the gain of the single spiral antenna at f/sub 0/. The frequency bandwidth for a 3-dB axial ratio criterion is almost the same as that of the single spiral antenna.

83 citations

Journal ArticleDOI
TL;DR: The measured data obtained from the CCD polarimeters matches the theoretical derivations of the temporal noise model of the Stokes parameters and is verified with measurements from an integrated polarization imaging sensor composed of a CCD imaging array and aluminum nanowire polarization filters.
Abstract: An analysis of the temporal noise in the Stokes parameters computed by division of focal plane polarimeters is presented. Theoretical estimations of the Stokes parameter signal-to-noise ratios for CCD polarization imaging sensors with both 4-polarizer and 2-polarizer micropolarization filter arrays are derived. The theoretical derivation is verified with measurements from an integrated polarization imaging sensor composed of a CCD imaging array and aluminum nanowire polarization filters. The measured data obtained from the CCD polarimeters matches the theoretical derivations of the temporal noise model of the Stokes parameters.

83 citations

Journal ArticleDOI
TL;DR: The state of polarization of strongly focused, radially polarized electromagnetic fields is examined, and it is demonstrated that on smoothly varying a system parameter, such as the aperture angle of the lens, different polarization singularities can annihilate each other.
Abstract: The state of polarization of strongly focused, radially polarized electromagnetic fields is examined. It is found that several types of polarization singularities exist. Their relationship is investigated, and it is demonstrated that on smoothly varying a system parameter, such as the aperture angle of the lens, different polarization singularities can annihilate each other. For example, the evolution of a lemon into a monstar and its subsequent annihilation with a star is studied. Also, the quite rare collision of a C-line and an L-line, resulting in a V-point, is observed.

83 citations

Journal ArticleDOI
TL;DR: In this article, a metamaterial design for realizing inhomogeneous and anisotropic effective media based on the localized waveguide resonance mechanism is proposed, which can be easily achieved in experiment and enables us to simultaneously manipulate the wavefront and the state of polarization of the transmitted electromagnetic field by the polarization sensitive extraordinary optical transmission.
Abstract: We propose a metamaterial design for realizing inhomogeneous and anisotropic effective media based on the localized waveguide resonance mechanism. Such a design can be easily achieved in experiment and enables us to simultaneously manipulate the wavefront and the state of polarization of the transmitted electromagnetic field by the polarization-sensitive extraordinary optical transmission. Numerical simulations, including the generation of the hybridized vector fields (especially twisted vector fields that are azimuthally polarized carrying a helical phase), prove the feasibility of our proposal. It could be expected as a good candidate of the specially designed subwavelength element for creating the exotic vector fields beyond the functionality of the existing vector fields in a wide spectral regime, especially the terahertz and radio regimes.

82 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023384
2022821
2021685
2020927
20191,060
2018968