Metasurface is a momentous periodic or aperiodic microstructure which has capabilities in controlling polarization of electromagnetic waves. To realize polarization controlling, many microstructures ...have been designed to achieve the function. However, multi‐band linear to dual‐circular polarization converter is rarely proposed and designed in the last few years. Here, a quad‐band dual‐circular transmissive metasurface (QCT‐MS) is proposed to manipulate polarization of transmissive wave. QCT‐MS is designed as a three‐layer microstructure, with substrate in the middle and two metal patches in the shape of bi‐symmetrical arrow on both sides. The proposed microstructure manipulates linear polarization waves to dual‐circular polarization waves in different frequency bands with x‐polarized or y‐polarized incident waves. The experimental and simulated results reveal that left‐hand circularly polarized waves can be realized in 3.14–3.32, 4.41–4.46, and 14.82–16.05 GHz while the right‐hand circularly polarized waves can be achieved from 9.45 to 10.12 GHz for QCT‐MS with x‐polarized incidences. Moreover, the simulated results also demonstrate its characteristics of wide‐angle transmission and periodic changes. The proposed transmissive metasurface can be utilized in multiband communication and multifunctional dual‐circularly polarized antenna systems.
A quad‐band dual‐circular transmissive metasurface is proposed to manipulate polarization of transmissive wave. The metasurface converts linear polarization wave to dual‐circular polarization wave in different frequency bands with different polarized incidences and has application in multiband communication and multifunctional dual‐circularly polarized antenna systems.
Zwei umschlungene rechte Hände werden für den Bau von “La Cathédrale” von Auguste Rodin benötigt. Zwei rechtshändige helikale Liganden sind notwendig, um CPL‐emittierende Komplexe vom Rubin‐Typ zu ...entwerfen, wie Juan‐Ramón Jiménez, Claude Piguet et al. in ihrem Forschungsartikel auf S. 10183 berichten.
In this paper, a novel dual‐band dual‐polarized leaky‐wave antenna (LWA) with polarization diversity is proposed using half mode substrate‐integrated waveguide (HMSIW)‐based technology. HMSIW LWAs ...are generally single band. In this work, by etching simple spiral type slots on the HMSIW cavity, a novel dual‐band dual‐polarized LWA is designed. The proposed antenna resonates at 5.6 and 8.5 GHz. Moreover, the antenna radiates the linearly polarized wave in the lower band and circularly polarized (CP) wave in the higher operating band. Also, in the higher operating band between 8.7 and 9.3 GHz, the proposed overall antenna exhibits both right‐hand circular polarization as well as the left‐hand circular polarization in the near main beam direction. The −10 dB impedance bandwidth of the proposed antenna at the lower and the higher operating bands are 27% (4.86‐6.4 GHz) and 25% (7.4‐9.6 GHz), respectively. In the higher band, the 3‐dB axial ratio bandwidth of 6.6% (8.7‐9.3 GHz) is achieved. The main beam of the antenna can be steered from 19° to 69° in the forward direction in the lower operating band. In the higher operating band, the antenna can steer the CP beam between −17° and −32°. In both the lower bands, the realized peak gain is observed around 13.3 dBi, whereas in the higher band, the realized peak gain is observed around 14 dBi.
Vortex beam carrying orbital angular momentum (OAM) has been widely explored in optical and microwave regions attributed to its potential characteristics in communication systems. For circular ...polarization incidence, Pancharatnam–Berry (PB) phase is a direct resource to generate phase gradient along the azimuthal direction required by specific OAM mode. The main drawback of PB phase is that it only affects cross‐polarized fields and keeps the copolarized part unmodulated. Here, a paradigm‐shift perspective of noninterleaved metasurfaces is proposed, which can simultaneously generate separate multiple integer and fractional OAM modes occupying both copolarized and cross‐polarized output channels. The scheme is validated by a series of experimental demonstrations in the microwave regime. By adjusting the polarization states of both input and receiving ends, different integer and fractional OAM modes are demonstrated in the full transmission channels. The results offer a unique recipe to enhance information capacity of metasurfaces and trigger versatile electromagnetic (EM) wave function integrations for advanced compact systems. A variety of applications can be readily expected in spin‐selective optics, spin‐Hall metadevices, and multitask metasurfaces operating in both reflection and transmission modes.
A general scheme is proposed to construct noninterleaved metasurface for generating multiple integer and fractional orbital angular momentum modes through altering the polarization state of the input and output ends. The co‐ and cross‐polarized output channels are completely utilized based on geometric and propagation phase modulations, and the transmitted energy is fully applied to implement five distinct vortex wavefronts.
Modern K/Ka-band satellite communications have become increasingly demanding in recent years with regard to the performance of the terminal antenna used in the link. These terminals should be ...high-gain and broadband, as well as guarantee polarization diversity over a large field-of-view. A low-profile is also highly desired to integrate the antenna system into a variety of moving platforms such as aircraft and trains. An ultra-low-profile continuous transverse stub array is proposed here to tackle these challenges. The antenna array is realized in printed circuit board technology by adopting a contact-less transition between the stacked-up layers without resorting to blind or buried vias. The proposed antenna is wideband (impedance matched within the band 19-31 GHz, i.e., ~ 50%) and provides multi-beam radiation for polar angles as far as ±22.5°. The peak value of the gain is 19.7 dBi and the maximum radiation efficiency equals 50%. Furthermore, the antenna array is combined with a dual-band polarization converter. The latter provides orthogonal circular polarization in two non-adjacent bands. The overall antenna system performs right- and left-hand circular polarization within the SatCom down- and up-links in the K/Ka-band, respectively. For each polarization, the axial ratio is below 3 dB over 9.47% and 4.42% fractional bandwidths, respectively.
Mutual coupling always seriously degrades the antenna performance in multiple-input multiple-output (MIMO) systems but this issue has been rarely investigated for antennas with circular polarization. ...In this paper, a planar and compact circularly polarized MIMO patch antenna with the polarization diversity is presented. Three grounded stubs and a mirrored F-shaped defected ground structure are used to achieve simultaneous matching and isolation between the two patches with offset feeding for circular polarization. The antenna elements are closely packed with the edge-to-edge distance of 0.06λ 0 at the desired frequency of 2.5 GHz. The measured results indicate that the proposed antenna achieves the impedance matching (S 11 <; -10 dB), high isolation (S 12 <; -20 dB), and circular polarization (axial ratio<; 3 dB) within the frequency band of 2.5-2.55 GHz. The radiation patterns and realized gains are measured, showing good agreement between the simulation and measurement.
Organic Electronics. In their Communication ( e202202977), Zikai He et al. report on the circularly polarized room‐temperature phosphorescence of a bidibenzob,dfuran scaffold with locked axial ...chirality.
Many wireless communication applications such as satellite communications use circularly polarized (CP) signals, with the requirement for easy switching of the polarization sense between uplink and ...downlink. Specifically, in satellite communications, the trend is also to move to higher frequencies and integrate the receiving and transmitting antennas in one dual-band terminal. However, these simultaneous demands make the design and fabrication of the composing parts very challenging. We propose, here, a dual-band dual-linear polarization (LP)-to-CP converter that works in the transmission mode. The working principle of this polarizer is explained through an example for Ka-band satellite communications at 19.7–20.2 and 29.5–30 GHz. The LP-to-CP converter is a single panel composed of identical unit cells with a thickness of only 1.05 mm and a size of 5.3 mm Formula Omitted mm. Due to its operation in the transmission mode, the polarizer can be combined with a simple dual-band dual-LP antenna to obtain the desired dual-band dual-CP single antenna. However, the unique property of this polarizer is yet the fact that it converts a given LP wave, e.g., x-polarization, to orthogonal CP waves at the two nonadjacent frequency bands, e.g., left-handed CP at lower band and right-handed CP at higher band. The polarizer is tested both with 20 and 30 GHz LP rectangular horns to illuminate a dual-band transmit array (TA) to obtain wide-angle steering of CP beams. The performance of the polarizer and its association with the TA is evaluated through simulation and measurements. We also present design guidelines for this type of polarizer.
Invited for the cover of this issue is the group of Koji Miki, Kouichi Ohe, and colleagues at Kyoto University. The image depicts mythical dragons as carbon‐based double helicates. Read the full text ...of the article at 10.1002/chem.201901467.
“a “flexible” carbon‐based double helicate, that dynamically forms an intramolecular excimer under photoirradiation, has been developed. Furthermore, the intramolecular excimer emits strong near‐infrared circularly polarized luminescence. This report offers the new approach to prepare near‐infrared CPL emitters.” Read more about the story behind the cover in the Cover Profile and about the research itself on page 9211 ff. (DOI: 10.1002/chem.201901467).
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