This paper describes a novel dual-feed circularly polarized antenna,and the dual feeding mode is realized by grooving on the antenna radiator.The antenna utilizes air dielectric material to meet the requirements of lo...This paper describes a novel dual-feed circularly polarized antenna,and the dual feeding mode is realized by grooving on the antenna radiator.The antenna utilizes air dielectric material to meet the requirements of low weight and cost.Test results demonstrate that the antenna exhibits capacitive loading between the metal antenna patch and the ground floor,allowing for adjustment of the working frequency of the dual-feed circularly polarized microstrip antenna.Specifically,the original center frequency of 2.264 GHz was reduced to 1.582 GHz,facilitating antenna miniaturization and broad bandwidth.With a return loss(S11)below-10 dB,a bandwidth of 72 MHz(1.552-1.624 GHz)was obtained.Additionally,the dual-feed microstrip antenna incorporates a 90°bridge,resulting in circular polarization gains of 2.26 dBi at 1.561 GHz and 2.45 dBi at 1.575 GHz.Overall,the antenna design offers a large working bandwidth and excellent circular polarization characteristics,making it suitable for a wide range of applications in satellite navigation and positioning terminals.展开更多
This paper presents an AMC(artificial magnetic conductor)-based wideband circularly polarized printed monopole antenna for unidirectional radiation.The antenna includes an AMC reflector,a coplanar waveguide(CPW)feed s...This paper presents an AMC(artificial magnetic conductor)-based wideband circularly polarized printed monopole antenna for unidirectional radiation.The antenna includes an AMC reflector,a coplanar waveguide(CPW)feed structure to excite the antenna,a ground plane with a rectangular slot on the left side of feedline,and an asymmetrical ground plane on its right side.The induced surface currents on CWP feedline,rectangularly slotted,and asymmetrical ground planes cause circularly polarized radiations.The AMC reflector consisting periodic metallic square patches is used instead of the conventional PEC(perfect electric conductor)reflector,the distance between the antenna and reflector is reduced from 0.25λ0 to 0.18λ0 with performance improvement.By incorporating AMC layer with the monopole antenna,the gain of antenna is increased from 3.3 dBic to 8.7 dBic while the axial ratio bandwidth(ARBW)of antenna is increased from 27.27%to 51.67%.The simulated and measured results show that the proposed antenna has an overlapping 10-dB|S_(11)|and 3-dB ARBW of 51.67%(3.0–5.09 GHz).The overall dimensions of monopole antenna backed by AMC reflector is 1.20_(λ0)×1.20_(λ0)×0.21_(λ0) and covers 5G sub-6 GHz new radio bands(n77/n78/n79)for wireless communication systems.展开更多
A single-layer design of non-uniform metasurface(MS)based circularly polarized(CP)antenna with wideband operation characteristic is proposed and investigated in this paper.The antenna is excited by a truncated corner ...A single-layer design of non-uniform metasurface(MS)based circularly polarized(CP)antenna with wideband operation characteristic is proposed and investigated in this paper.The antenna is excited by a truncated corner squared patch as a primary radiating CP source.Then,a non-uniform MS is placed in the same layer with the driven patch.Besides increasing the impedance bandwidth,the non-uniform MS also generates two additional CP bands in the high frequency band,leading to significantly increase the antenna’s overall performances.The use of non-uniform MS distinguishes our design from the other CP MS based antennas in literature,in which the MS is formed by multiple uniform unit cells and placed in different layer with the radiating element.For validation,an antenna prototype,whose overall dimensions of 0.94λ_(o)×0.94λ_(o)×0.06λ_(o) at the center operating frequency,is fabricated and experimentally tested.The measured operating bandwidth with|S11|≤−10 dB and AR≤3 dB is 27.1%(5.1–6.7 GHz)and the broadside gain within this band is from 5.7 to 7.2 dBic.Compared to the other related works,the proposed antenna has advantage of very wideband operation with single-layer design.展开更多
A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface(GPGM).With an accuracy control of the transmiss...A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface(GPGM).With an accuracy control of the transmission phase and also the high transmission amplitude,the GPGM is capable of manipulating an electromagnetic wave arbitrarily.A focusing transmission lens working at Ku band is well optimized with the F /D of 0.32.A good focusing effect is demonstrated clearly by theoretical calculation and electromagnetic simulation.For further application,an ultra-thin single-layer transmissive lens antenna based on the proposed focusing metasurface operating at 13 GHz is implemented and launched by an original patch antenna from the perspective of high integration,simple structure,and low cost.Numerical and experimental results coincide well,indicating the advantages of the antenna system,such as a high gain of 17.6 d B,the axis ratio better than 2 d B,a high aperture efficiency of 41%,and also a simple fabrication process based on the convenient print circuit board technology.The good performance of the proposed antenna indicates promising applications in portable communication systems.展开更多
Range measurement has found multiple applications in deep space missions. With more and further deep space ex- ploration activities happening now and in the future, the requirement for range measurement has risen. In ...Range measurement has found multiple applications in deep space missions. With more and further deep space ex- ploration activities happening now and in the future, the requirement for range measurement has risen. In view of the future ranging requirement, a novel x-ray polarized ranging method based on the circular polarization modulation is proposed, termed as x-ray circularly polarized ranging (XCPolR). XCPolR utilizes the circular polarization modulation to process x-ray signals and the ranging information is conveyed by the circular polarization states. As the circular polarization states present good stability in space propagation and x-ray detectors have light weight and low power consumption, XCPolR shows great potential in the long-distance range measurement and provides an option for future deep space ranging. In this paper, we present a detailed illustration of XCPolR. Firstly, the structure of the polarized ranging system is described and the signal models in the ranging process are established mathematically. Then, the main factors that affect the ranging accuracy, including the Doppler effect, the differential demodulation, and the correlation error, are analyzed theoretically. Finally, numerical simulation is carded out to evaluate the performance of XCPolR.展开更多
A compact and broadband circularly polarized (CP) annular ring antenna with wide beam-width is proposed for multiple global navigation satellite systems (GNSS) in the L1 band. The annular ring is excited by two mo...A compact and broadband circularly polarized (CP) annular ring antenna with wide beam-width is proposed for multiple global navigation satellite systems (GNSS) in the L1 band. The annular ring is excited by two modified L-probes with quadrature phase difference. It has a 36.3% 10-dB return loss bandwidth and a 13% 3-dB axial ratio bandwidth, because of the orthogonal L-probes with 90° phase difference. The measured peak gain of the antenna is 3.9 dBic. It can detect the satellites at lower elevation as its half power beam-width (HPBW) is 113° in both the x-z and y-z planes, achieving a cross-polarization level of larger than 25 dB. Noticeably, the antenna achieves 89% size reduction compared with the conventional half wavelength patch antennas. It can be used in hand-held navigation devices of multiple GNSS such as COMPASS, Galileo, GPS and GLONASS.展开更多
A ceramic dielectric resonator antenna excited by a corner-cut square patch for the circularly-polarized operation is introduced. The effect of patch size and cut size is investigated, showing that the resonant freque...A ceramic dielectric resonator antenna excited by a corner-cut square patch for the circularly-polarized operation is introduced. The effect of patch size and cut size is investigated, showing that the resonant frequency of the antenna can be changed by simply changing the patch size. The reflection, axial ratio, and radiation characteristics of the antenna are found. Measurements were carried out to verify the design. The antenna is compact in structure, which is attractive in the application as the satellite communication terminals.展开更多
Development of textile antennas is an important segment towards the goal of creating smart clothing. In this paper, we report on a jeans-based circularly polarized textile antenna designed for the E-band (around 2.45 ...Development of textile antennas is an important segment towards the goal of creating smart clothing. In this paper, we report on a jeans-based circularly polarized textile antenna designed for the E-band (around 2.45 GHz). We present three variations of the design and the respective results. The antenna comprises a multi-layer jeans-fabric as the substrate, a conductive fabric as the patch, which is concealed with another layer of jeans, and the ground plane is formed by either a cooper foil or another conductive fabric. A multi-layer structure was chosen to provide a wider bandwidth and better efficiency, whereas the upper surface of the antenna was covered by one more layer of jeans to both make the antenna less conspicuous, when worn on the arm, and protect the patch and substrate from mechanical damages and moisture. All three variants are characterized by a good realized gain of about 3 dB, a wide beam width and a wide bandwidth of 21% or better, around 2.45 GHz, having the radiation efficiency around 36%, and front-to-back ratio of 5 dB or better, with the ground plane being just slightly larger than the patch.展开更多
Circularly polarized microstrip antenna is frequently realized by cutting the slot inside the patch and feeding it along the diagonal axis. In the reported literature, procedure to design them at any given frequency i...Circularly polarized microstrip antenna is frequently realized by cutting the slot inside the patch and feeding it along the diagonal axis. In the reported literature, procedure to design them at any given frequency is not available. In proposed work, circularly polarized slot cut circular microstrip antenna at 900 MHz is discussed. By studying the surface current distributions at two orthogonal modes, formulations in their resonant length are proposed. The frequencies calculated using them closely agree with simulated results. Using proposed formulation, procedure to design circular polarized antennas at different frequencies is presented that gives circular polarized response. Thus, proposed work will be helpful to design similar circular polarized circular microstrip antenna at any desired frequency.展开更多
If a metalens integrates the circular polarization(CP)conversion function,the focusing lens together with circular-polariz-ing lens(CPL)in traditional cameras may be replaced by a metalens.However,in terahertz(THz)ban...If a metalens integrates the circular polarization(CP)conversion function,the focusing lens together with circular-polariz-ing lens(CPL)in traditional cameras may be replaced by a metalens.However,in terahertz(THz)band,the reported metalenses still do not obtain the perfect and strict single-handed CP,because they were constructed via Pancharatnam-Berry phase so that CP conversion contained both left-handed CP(LCP)and right-handed CP(RCP)components.In this paper,a silicon based THz metalens is constructed using dynamic phase to obtain single-handed CP conversion.Also,we can rotate the whole metalens at a certain angle to control the conversion of multi-polarization states,which can simply manipulate the focusing for incident linear polarization(LP)THz wave in three polarization conversion states,in-cluding LP without conversion,LCP and RCP.Moreover,the polarization conversion behavior is reversible,that is,the THz metalens can convert not only the LP into arbitrary single-handed CP,but also the LCP and RCP into two perpen-dicular LP,respectively.The metalens is expected to be used in advanced THz camera,as a great candidate for tradi-tional CPL and focusing lens group,and also shows potential application in polarization imaging with discriminating LCP and RCP.展开更多
In this paper, we show that circular polarization-keeping reflection can be achieved using reflective metasurfaces. The underlying physical mechanism of the polarization-keeping reflection is analyzed using a reflecti...In this paper, we show that circular polarization-keeping reflection can be achieved using reflective metasurfaces. The underlying physical mechanism of the polarization-keeping reflection is analyzed using a reflection matrix. A wideband circular polarization-keeping reflector is demonstrated using N-shaped resonators. Both the simulation and experiment results show that the polarization-keeping reflection can be achieved with a high efficiency larger than 98% over the frequency range from 9.2 GHz to 17.7 GHz for both incident left- and right-handed circularly polarized waves. Under oblique incidence, the bandwidth increases as the incident angle varies from 0°to 80°. Moreover, the co-polarization reflection is independent of the incident azimuth angles.展开更多
<div style="text-align:justify;"> Metasurfaces have shown great potential in controlling the propagation of electromagnetic waves, making them suitable for holographic beam-shaping elements. Using the ...<div style="text-align:justify;"> Metasurfaces have shown great potential in controlling the propagation of electromagnetic waves, making them suitable for holographic beam-shaping elements. Using the principle of array synthesis, holograms have been realized in microwave frequency to manipulate electromagnetic waves to generate specific field patterns. However, current research is almost based on linear polarization and has little analysis on the circular polarization microwave hologram. Herein, we propose a circular polarization hologram realized by sub-wavelength units with self-adaptively phase profiles of electromagnetic waves. The full, continuous control of the phase is achieved by using a single structure unit based on the Pancharatnam-Berry phase. The inhomogeneity of wave-front is considered through amplitude and phase compensation which are essential to improve the quality of microwave hologram. The model achieves circular polarization hologram in microwave frequency and the clear field pattern is generated. The circular polarization hologram enriched the research field of microwave imaging, thus providing more inspirations for the development of various related techniques. </div>展开更多
Just like an electronic diode that allows the electrical current to flow in one direction only, a kind of chiral metamaterial structure with a similar functionality for the electromagnetic wave is proposed. The design...Just like an electronic diode that allows the electrical current to flow in one direction only, a kind of chiral metamaterial structure with a similar functionality for the electromagnetic wave is proposed. The designed nanostructure that consists of twisted metallic split-ring resonators on both sides of a dielectric substrate achieves asymmetric transmission for a forward and backward propagating linearly polarized wave by numerical simulation in near-infrared band. Difference in transmission efficiency of the optimized structure between the same polarized waves incident from opposite directions can reach a maximum at the communication wavelength (1.55 μm). Moreover, the simulation results of this structure also exhibit strong optical activity and circular dichroism.展开更多
We theoretically investigate the strong-field ionization of H+2 molecules in four different electronic states by calculating photoelectron angular distributions in circularly polarized fields. We find that the struct...We theoretically investigate the strong-field ionization of H+2 molecules in four different electronic states by calculating photoelectron angular distributions in circularly polarized fields. We find that the structure of photoelectron angular distribution depends on the molecular orbital as well as the energy of the photoelectron. The location of main lobes changes with the symmetric property of the molecular orbital. Generally, for molecules with bonding electronic states, the photoelectron’s angular distribution shows a rotation of π/2 with respect to the molecular axis, while for molecules with antibonding electronic states, no rotation occurs. We use an interference scenario to interpret these phenomena. We also find that, due to the interference effect, a new pair of jets appears in the waist of the main lobes, and the main lobes or jets of the photoelectron’s angular distribution are split into two parts if the photoelectron energy is sufficiently high.展开更多
A multi-band circular polarizer using a twisted triple split-ring resonator(TSRR) is presented and studied numerically and experimentally. At four distinct resonant frequencies, the incident linearly polarized wave ...A multi-band circular polarizer using a twisted triple split-ring resonator(TSRR) is presented and studied numerically and experimentally. At four distinct resonant frequencies, the incident linearly polarized wave can be transformed into left/right-handed circularly polarized waves. Numerical simulation results show that a y-polarized wave can be converted into a right-handed circularly polarized wave at 5.738 GHz and 9.218 GHz, while a left-handed circularly polarized wave is produced at 7.292 GHz and 10.118 GHz. The experimental results are in agreement with the numerical results. The surface current distributions are investigated to illustrate the polarization transformation mechanism. Furthermore, the influences of the structure parameters of the circular polarizer on transmission spectra are discussed as well.展开更多
A reflectarray antenna consisting of asymmetrical patch elements is proposed,which is capable of producing dual linear and dual circular polarized operation at 26GHz frequency.The main purpose of this design is to sup...A reflectarray antenna consisting of asymmetrical patch elements is proposed,which is capable of producing dual linear and dual circular polarized operation at 26GHz frequency.The main purpose of this design is to support four different polarizations using the same patch element.The proposed reflectarray has a single layer configuration with a linearly polarized feed and circular ring slots in the ground plane.Asymmetric patch element is designed from a square patch element by tilting its one vertical side to some optimized inclination.A wide reflection phase range of 600°is obtained with the asymmetric patch element during unit cell measurements.A 332 element circular aperture reflectarray is designed with the proposed configuration and experimentally validated with a linearly polarized prime feed configuration.Two different orientations of mirror and non-mirror asymmetric patch elements on the surface of reflectarray are analyzed.Dual linear polarization is obtained with the mirror orientation of the asymmetric patch elements on the surface of reflectarray.Alternatively,asymmetric patch elements without mirror orientation are demonstrated to produce dual circular polarization with the same linearly polarized feed.A maximum measured gain of 24.4 dB and 26.1 dB is achieved for dual linear and dual circular polarization,respectively.Their respective measured efficiencies are 28%and 41.3%,which are supported by amaximum−3 dB gain bandwidth of 13.8%and 11.5%.The circular polarization operation of the reflectarray is also supported by a 6 dB axial ratio bandwidth of 9.2%.The proposed asymmetric patch reflectarray antenna with polarization diversity,wide bandwidth and high gain is suitable to be used in many high frequency applications of 5G communication.展开更多
An ultra-wideband and high-efficiency reflective linear-to-circular polarization conversion metasurface is proposed. The proposed metasurface is composed of a square array of a corner-truncated square patch printed on...An ultra-wideband and high-efficiency reflective linear-to-circular polarization conversion metasurface is proposed. The proposed metasurface is composed of a square array of a corner-truncated square patch printed on grounded dielectric substrate and covered with a dielectric layer, which is an orthotropic anisotropic structure with a pair of mutually perpendicular symmetric axes u and v along the directions with the tilt angles of ±45° with respect to the vertical y axis. When the u- and v-polarized waves are incident on the proposed metasurface, the phase difference between the two reflection coefficients is close to –90° in an ultra-wide frequency band, so it can realize high-efficiency and ultra-wideband LTC polarization conversion under both x- and y-polarized incidences in this band. The proposed polarization conversion metasurface is simulated and measured. Both the simulated and measured results show that the axial ratio (AR) of the reflected wave is kept below 3 dB in the ultra-wide frequency band of 5.87 GHz–21.13 GHz, which is corresponding to a relative bandwidth of 113%;moreover, the polarization conversion rate (PCR) can be kept larger than 99% in a frequency range of 8.08 GHz–20.92 GHz.展开更多
We propose a metasurface which consists of three conductive layers separated by two dielectric layers. Each conductive layer consists of a square array of square loop apertures, however, a pair of corners of each squa...We propose a metasurface which consists of three conductive layers separated by two dielectric layers. Each conductive layer consists of a square array of square loop apertures, however, a pair of corners of each square metal patch surrounded by the square loop apertures have been truncated, so it becomes an orthotropic structure with a pair of mutually perpendicular symmetric axes u and v. The simulated results show that the metasurface can be used as a wideband transmission-type polarization converter to realize linear-to-circular polarization conversion in the frequency range from12.21 GHz to 18.39 GHz, which is corresponding to a 40.4% fractional bandwidth. Moreover, its transmission coefficients at x-and y-polarized incidences are completely equal. We have analyzed the cause of the polarization conversion, and derived several formulas which can be used to calculate the magnitudes of cross-and co-polarization transmission coefficients at y-polarized incidence, together with the phase difference between them, based on the two independent transmission coefficients at u-and v-polarized incidences. Finally, one experiment was carried out, and the experiment and simulated results are in good agreement with each other.展开更多
Bell tests with entangled light have been performed many times in many ways using linear polarizers, but the same tests have never been done with a circular polarizer. Until recently there has never been a true circul...Bell tests with entangled light have been performed many times in many ways using linear polarizers, but the same tests have never been done with a circular polarizer. Until recently there has never been a true circular polarization beamsplitter—an optical component that separates light directly into left and right handed polarizations. Using a true circular polarization beamsplitter based on birefringent gratings, entangled light has been analyzed with unexpected results.展开更多
Chiral two-dimensional(2D) perovskites offer numerous attractive features for optoelectronics owing to their soft, deformable lattices and a high degree of chemical tunability. While tremendous advances have been made...Chiral two-dimensional(2D) perovskites offer numerous attractive features for optoelectronics owing to their soft, deformable lattices and a high degree of chemical tunability. While tremendous advances have been made in perovskite-based direct circularly polarized light(CPL) detection, the low circular polarization anisotropy factor and sensitivity of those photodetectors arising from large lattice distortion still limit practical applications. Herein, chiral 2D perovskite-based single-crystalline microwire arrays with enhanced circular dichroism(CD) absorption are fabricated with the synergy of the capillary-bridgeconfined assembly method and chlorine-substituted phenethylamine(Cl-MBA). Compared with phenethylamine(MBA)-inserted perovskites, the smaller lattice distortion and increased halogen–halogen interaction within Cl–MBA-inserted perovskites strengthen lattice rigidity and weaken electron–phonon coupling to improve carrier transport and thermal stability, resulting in high-performance CPL photodetectors with an anisotropy factor of 0.25, responsivity exceeding 95.7±9.3 A W^(-1)and detectivity exceeding(3.05±0.30)×10^(13)Jones. This work opens a new perspective to modulate circular polarization sensitivity and will be helpful to realize promising implementations in quantum computation and communication.展开更多
文摘This paper describes a novel dual-feed circularly polarized antenna,and the dual feeding mode is realized by grooving on the antenna radiator.The antenna utilizes air dielectric material to meet the requirements of low weight and cost.Test results demonstrate that the antenna exhibits capacitive loading between the metal antenna patch and the ground floor,allowing for adjustment of the working frequency of the dual-feed circularly polarized microstrip antenna.Specifically,the original center frequency of 2.264 GHz was reduced to 1.582 GHz,facilitating antenna miniaturization and broad bandwidth.With a return loss(S11)below-10 dB,a bandwidth of 72 MHz(1.552-1.624 GHz)was obtained.Additionally,the dual-feed microstrip antenna incorporates a 90°bridge,resulting in circular polarization gains of 2.26 dBi at 1.561 GHz and 2.45 dBi at 1.575 GHz.Overall,the antenna design offers a large working bandwidth and excellent circular polarization characteristics,making it suitable for a wide range of applications in satellite navigation and positioning terminals.
基金This work was supported in parts by Institute for Information and Communication Technology Promotion(IITP)(A study on Public Health and Safety in a Complex EMF Environment),under Grant 2019-0-00102,and in part by Radio Research Agency(RRA)(Development of Rapid Antenna Measurement Technique for Antennas with New Radio Technology).
文摘This paper presents an AMC(artificial magnetic conductor)-based wideband circularly polarized printed monopole antenna for unidirectional radiation.The antenna includes an AMC reflector,a coplanar waveguide(CPW)feed structure to excite the antenna,a ground plane with a rectangular slot on the left side of feedline,and an asymmetrical ground plane on its right side.The induced surface currents on CWP feedline,rectangularly slotted,and asymmetrical ground planes cause circularly polarized radiations.The AMC reflector consisting periodic metallic square patches is used instead of the conventional PEC(perfect electric conductor)reflector,the distance between the antenna and reflector is reduced from 0.25λ0 to 0.18λ0 with performance improvement.By incorporating AMC layer with the monopole antenna,the gain of antenna is increased from 3.3 dBic to 8.7 dBic while the axial ratio bandwidth(ARBW)of antenna is increased from 27.27%to 51.67%.The simulated and measured results show that the proposed antenna has an overlapping 10-dB|S_(11)|and 3-dB ARBW of 51.67%(3.0–5.09 GHz).The overall dimensions of monopole antenna backed by AMC reflector is 1.20_(λ0)×1.20_(λ0)×0.21_(λ0) and covers 5G sub-6 GHz new radio bands(n77/n78/n79)for wireless communication systems.
文摘A single-layer design of non-uniform metasurface(MS)based circularly polarized(CP)antenna with wideband operation characteristic is proposed and investigated in this paper.The antenna is excited by a truncated corner squared patch as a primary radiating CP source.Then,a non-uniform MS is placed in the same layer with the driven patch.Besides increasing the impedance bandwidth,the non-uniform MS also generates two additional CP bands in the high frequency band,leading to significantly increase the antenna’s overall performances.The use of non-uniform MS distinguishes our design from the other CP MS based antennas in literature,in which the MS is formed by multiple uniform unit cells and placed in different layer with the radiating element.For validation,an antenna prototype,whose overall dimensions of 0.94λ_(o)×0.94λ_(o)×0.06λ_(o) at the center operating frequency,is fabricated and experimentally tested.The measured operating bandwidth with|S11|≤−10 dB and AR≤3 dB is 27.1%(5.1–6.7 GHz)and the broadside gain within this band is from 5.7 to 7.2 dBic.Compared to the other related works,the proposed antenna has advantage of very wideband operation with single-layer design.
基金Project supported by the National Natural Science Foundation of China(Grant No.61372034)
文摘A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface(GPGM).With an accuracy control of the transmission phase and also the high transmission amplitude,the GPGM is capable of manipulating an electromagnetic wave arbitrarily.A focusing transmission lens working at Ku band is well optimized with the F /D of 0.32.A good focusing effect is demonstrated clearly by theoretical calculation and electromagnetic simulation.For further application,an ultra-thin single-layer transmissive lens antenna based on the proposed focusing metasurface operating at 13 GHz is implemented and launched by an original patch antenna from the perspective of high integration,simple structure,and low cost.Numerical and experimental results coincide well,indicating the advantages of the antenna system,such as a high gain of 17.6 d B,the axis ratio better than 2 d B,a high aperture efficiency of 41%,and also a simple fabrication process based on the convenient print circuit board technology.The good performance of the proposed antenna indicates promising applications in portable communication systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.61172138 and 61401340)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2013JQ8040)+4 种基金the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20130203120004)the Open Research Fund of the Academy of Satellite Application,China(Grant No.2014 CXJJ-DH 12)the Xi’an Science and Technology Plan,China(Grant No.CXY1350(4))the Fundamental Research Funds for the Central Universities,China(Grant Nos.201413B,201412B,and JB141303)the Open Fund of Key Laboratory of Precision Navigation and Timing Technology,National Time Service Center,Chinese Academy of Sciences(Grant Nos.2014PNTT01,2014PNTT07,and 2014PNTT08)
文摘Range measurement has found multiple applications in deep space missions. With more and further deep space ex- ploration activities happening now and in the future, the requirement for range measurement has risen. In view of the future ranging requirement, a novel x-ray polarized ranging method based on the circular polarization modulation is proposed, termed as x-ray circularly polarized ranging (XCPolR). XCPolR utilizes the circular polarization modulation to process x-ray signals and the ranging information is conveyed by the circular polarization states. As the circular polarization states present good stability in space propagation and x-ray detectors have light weight and low power consumption, XCPolR shows great potential in the long-distance range measurement and provides an option for future deep space ranging. In this paper, we present a detailed illustration of XCPolR. Firstly, the structure of the polarized ranging system is described and the signal models in the ranging process are established mathematically. Then, the main factors that affect the ranging accuracy, including the Doppler effect, the differential demodulation, and the correlation error, are analyzed theoretically. Finally, numerical simulation is carded out to evaluate the performance of XCPolR.
基金supported by the NSFC-Guangdong (Grant No.U1035002) and NSFC-NSAF (Grant No.10976010)National Key Project of Science and Technology of China (Grant No. 2009ZX03006-003)the Technology Key Projects of Guangdong Province of China (Grant Nos.2009A080207006 and 2009A080207002)
文摘A compact and broadband circularly polarized (CP) annular ring antenna with wide beam-width is proposed for multiple global navigation satellite systems (GNSS) in the L1 band. The annular ring is excited by two modified L-probes with quadrature phase difference. It has a 36.3% 10-dB return loss bandwidth and a 13% 3-dB axial ratio bandwidth, because of the orthogonal L-probes with 90° phase difference. The measured peak gain of the antenna is 3.9 dBic. It can detect the satellites at lower elevation as its half power beam-width (HPBW) is 113° in both the x-z and y-z planes, achieving a cross-polarization level of larger than 25 dB. Noticeably, the antenna achieves 89% size reduction compared with the conventional half wavelength patch antennas. It can be used in hand-held navigation devices of multiple GNSS such as COMPASS, Galileo, GPS and GLONASS.
基金Project supported by the National High-Technology Research and Development Project of China (Grant No.2007AA12Z125)the Innovation Foundation of Shanghai University (Grant No.SHUCX092130)
文摘A ceramic dielectric resonator antenna excited by a corner-cut square patch for the circularly-polarized operation is introduced. The effect of patch size and cut size is investigated, showing that the resonant frequency of the antenna can be changed by simply changing the patch size. The reflection, axial ratio, and radiation characteristics of the antenna are found. Measurements were carried out to verify the design. The antenna is compact in structure, which is attractive in the application as the satellite communication terminals.
基金supported in part by the University of Rijeka under the project number 1435.
文摘Development of textile antennas is an important segment towards the goal of creating smart clothing. In this paper, we report on a jeans-based circularly polarized textile antenna designed for the E-band (around 2.45 GHz). We present three variations of the design and the respective results. The antenna comprises a multi-layer jeans-fabric as the substrate, a conductive fabric as the patch, which is concealed with another layer of jeans, and the ground plane is formed by either a cooper foil or another conductive fabric. A multi-layer structure was chosen to provide a wider bandwidth and better efficiency, whereas the upper surface of the antenna was covered by one more layer of jeans to both make the antenna less conspicuous, when worn on the arm, and protect the patch and substrate from mechanical damages and moisture. All three variants are characterized by a good realized gain of about 3 dB, a wide beam width and a wide bandwidth of 21% or better, around 2.45 GHz, having the radiation efficiency around 36%, and front-to-back ratio of 5 dB or better, with the ground plane being just slightly larger than the patch.
文摘Circularly polarized microstrip antenna is frequently realized by cutting the slot inside the patch and feeding it along the diagonal axis. In the reported literature, procedure to design them at any given frequency is not available. In proposed work, circularly polarized slot cut circular microstrip antenna at 900 MHz is discussed. By studying the surface current distributions at two orthogonal modes, formulations in their resonant length are proposed. The frequencies calculated using them closely agree with simulated results. Using proposed formulation, procedure to design circular polarized antennas at different frequencies is presented that gives circular polarized response. Thus, proposed work will be helpful to design similar circular polarized circular microstrip antenna at any desired frequency.
基金supported by the National Natural Science Foundation of China(Nos.61675147,61735010 and 91838301)National Key Research and Development Program of China(No.2017YFA0700202)Basic Re-search Program of Shenzhen(JCYJ20170412154447469).
文摘If a metalens integrates the circular polarization(CP)conversion function,the focusing lens together with circular-polariz-ing lens(CPL)in traditional cameras may be replaced by a metalens.However,in terahertz(THz)band,the reported metalenses still do not obtain the perfect and strict single-handed CP,because they were constructed via Pancharatnam-Berry phase so that CP conversion contained both left-handed CP(LCP)and right-handed CP(RCP)components.In this paper,a silicon based THz metalens is constructed using dynamic phase to obtain single-handed CP conversion.Also,we can rotate the whole metalens at a certain angle to control the conversion of multi-polarization states,which can simply manipulate the focusing for incident linear polarization(LP)THz wave in three polarization conversion states,in-cluding LP without conversion,LCP and RCP.Moreover,the polarization conversion behavior is reversible,that is,the THz metalens can convert not only the LP into arbitrary single-handed CP,but also the LCP and RCP into two perpen-dicular LP,respectively.The metalens is expected to be used in advanced THz camera,as a great candidate for tradi-tional CPL and focusing lens group,and also shows potential application in polarization imaging with discriminating LCP and RCP.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.61331005,11204378,11274389,11304393,and 61302023)the National Natural Science Foundation of Shaanxi Province,China(Grant Nos.2011JQ8031 and 2013JM6005)
文摘In this paper, we show that circular polarization-keeping reflection can be achieved using reflective metasurfaces. The underlying physical mechanism of the polarization-keeping reflection is analyzed using a reflection matrix. A wideband circular polarization-keeping reflector is demonstrated using N-shaped resonators. Both the simulation and experiment results show that the polarization-keeping reflection can be achieved with a high efficiency larger than 98% over the frequency range from 9.2 GHz to 17.7 GHz for both incident left- and right-handed circularly polarized waves. Under oblique incidence, the bandwidth increases as the incident angle varies from 0°to 80°. Moreover, the co-polarization reflection is independent of the incident azimuth angles.
文摘<div style="text-align:justify;"> Metasurfaces have shown great potential in controlling the propagation of electromagnetic waves, making them suitable for holographic beam-shaping elements. Using the principle of array synthesis, holograms have been realized in microwave frequency to manipulate electromagnetic waves to generate specific field patterns. However, current research is almost based on linear polarization and has little analysis on the circular polarization microwave hologram. Herein, we propose a circular polarization hologram realized by sub-wavelength units with self-adaptively phase profiles of electromagnetic waves. The full, continuous control of the phase is achieved by using a single structure unit based on the Pancharatnam-Berry phase. The inhomogeneity of wave-front is considered through amplitude and phase compensation which are essential to improve the quality of microwave hologram. The model achieves circular polarization hologram in microwave frequency and the clear field pattern is generated. The circular polarization hologram enriched the research field of microwave imaging, thus providing more inspirations for the development of various related techniques. </div>
基金Project supported by the National Natural Science Foundation of China(Grant No.61078060)the Fund from the Ningbo Optoelectronic Materials and Devices Creative Team,China(Grant No.2009B21007)partially sponsored by K.C.Wong Magna Fund in Ningbo University
文摘Just like an electronic diode that allows the electrical current to flow in one direction only, a kind of chiral metamaterial structure with a similar functionality for the electromagnetic wave is proposed. The designed nanostructure that consists of twisted metallic split-ring resonators on both sides of a dielectric substrate achieves asymmetric transmission for a forward and backward propagating linearly polarized wave by numerical simulation in near-infrared band. Difference in transmission efficiency of the optimized structure between the same polarized waves incident from opposite directions can reach a maximum at the communication wavelength (1.55 μm). Moreover, the simulation results of this structure also exhibit strong optical activity and circular dichroism.
基金the National Natural Science Foundation of China(Grant Nos.11104167,11174304,and 61078080)the Excellent Middle-Aged and Youth Scientist Award of Shandong Province,China(Grant No.BS2011SF021) and the Scientific Research Foundation for the Returned Overseas Chinese Scholars
文摘We theoretically investigate the strong-field ionization of H+2 molecules in four different electronic states by calculating photoelectron angular distributions in circularly polarized fields. We find that the structure of photoelectron angular distribution depends on the molecular orbital as well as the energy of the photoelectron. The location of main lobes changes with the symmetric property of the molecular orbital. Generally, for molecules with bonding electronic states, the photoelectron’s angular distribution shows a rotation of π/2 with respect to the molecular axis, while for molecules with antibonding electronic states, no rotation occurs. We use an interference scenario to interpret these phenomena. We also find that, due to the interference effect, a new pair of jets appears in the waist of the main lobes, and the main lobes or jets of the photoelectron’s angular distribution are split into two parts if the photoelectron energy is sufficiently high.
基金Project supported by the National Natural Science Foundation of China(Grant No.41474117)the Special Funds for Development Scientific Research Unit Projects of Wuhan,China(Grant No.2013BJ004)
文摘A multi-band circular polarizer using a twisted triple split-ring resonator(TSRR) is presented and studied numerically and experimentally. At four distinct resonant frequencies, the incident linearly polarized wave can be transformed into left/right-handed circularly polarized waves. Numerical simulation results show that a y-polarized wave can be converted into a right-handed circularly polarized wave at 5.738 GHz and 9.218 GHz, while a left-handed circularly polarized wave is produced at 7.292 GHz and 10.118 GHz. The experimental results are in agreement with the numerical results. The surface current distributions are investigated to illustrate the polarization transformation mechanism. Furthermore, the influences of the structure parameters of the circular polarizer on transmission spectra are discussed as well.
基金The authors extend their appreciation to the Deanship of Scientific Research at Imam Mohammad Ibn Saud Islamic University for funding this work through Research Group No.RG-21-12-08.The initials of the authors who receive the grant are:ZAS.The URL of the sponsor’s website:https://units.imamu.edu.sa/deanships/sr/Pages/default.aspx.
文摘A reflectarray antenna consisting of asymmetrical patch elements is proposed,which is capable of producing dual linear and dual circular polarized operation at 26GHz frequency.The main purpose of this design is to support four different polarizations using the same patch element.The proposed reflectarray has a single layer configuration with a linearly polarized feed and circular ring slots in the ground plane.Asymmetric patch element is designed from a square patch element by tilting its one vertical side to some optimized inclination.A wide reflection phase range of 600°is obtained with the asymmetric patch element during unit cell measurements.A 332 element circular aperture reflectarray is designed with the proposed configuration and experimentally validated with a linearly polarized prime feed configuration.Two different orientations of mirror and non-mirror asymmetric patch elements on the surface of reflectarray are analyzed.Dual linear polarization is obtained with the mirror orientation of the asymmetric patch elements on the surface of reflectarray.Alternatively,asymmetric patch elements without mirror orientation are demonstrated to produce dual circular polarization with the same linearly polarized feed.A maximum measured gain of 24.4 dB and 26.1 dB is achieved for dual linear and dual circular polarization,respectively.Their respective measured efficiencies are 28%and 41.3%,which are supported by amaximum−3 dB gain bandwidth of 13.8%and 11.5%.The circular polarization operation of the reflectarray is also supported by a 6 dB axial ratio bandwidth of 9.2%.The proposed asymmetric patch reflectarray antenna with polarization diversity,wide bandwidth and high gain is suitable to be used in many high frequency applications of 5G communication.
基金Project supported by the Natural Science Foundation of Shaanxi Province, China (Grant Nos. 2019JM-077 and 2018JM-6098)the Scientific Research Program Funded by Shaanxi Provincial Education Department (Grant No. 18JK1195)the Shaanxi Key Research and Development Project, China (Grant No. 2019GY-055).
文摘An ultra-wideband and high-efficiency reflective linear-to-circular polarization conversion metasurface is proposed. The proposed metasurface is composed of a square array of a corner-truncated square patch printed on grounded dielectric substrate and covered with a dielectric layer, which is an orthotropic anisotropic structure with a pair of mutually perpendicular symmetric axes u and v along the directions with the tilt angles of ±45° with respect to the vertical y axis. When the u- and v-polarized waves are incident on the proposed metasurface, the phase difference between the two reflection coefficients is close to –90° in an ultra-wide frequency band, so it can realize high-efficiency and ultra-wideband LTC polarization conversion under both x- and y-polarized incidences in this band. The proposed polarization conversion metasurface is simulated and measured. Both the simulated and measured results show that the axial ratio (AR) of the reflected wave is kept below 3 dB in the ultra-wide frequency band of 5.87 GHz–21.13 GHz, which is corresponding to a relative bandwidth of 113%;moreover, the polarization conversion rate (PCR) can be kept larger than 99% in a frequency range of 8.08 GHz–20.92 GHz.
基金Project supported by the National Natural Science Foundation of China(Grant No.61471387)the Research Center for Internet of Things and Big Data Technology of Xijing University,China
文摘We propose a metasurface which consists of three conductive layers separated by two dielectric layers. Each conductive layer consists of a square array of square loop apertures, however, a pair of corners of each square metal patch surrounded by the square loop apertures have been truncated, so it becomes an orthotropic structure with a pair of mutually perpendicular symmetric axes u and v. The simulated results show that the metasurface can be used as a wideband transmission-type polarization converter to realize linear-to-circular polarization conversion in the frequency range from12.21 GHz to 18.39 GHz, which is corresponding to a 40.4% fractional bandwidth. Moreover, its transmission coefficients at x-and y-polarized incidences are completely equal. We have analyzed the cause of the polarization conversion, and derived several formulas which can be used to calculate the magnitudes of cross-and co-polarization transmission coefficients at y-polarized incidence, together with the phase difference between them, based on the two independent transmission coefficients at u-and v-polarized incidences. Finally, one experiment was carried out, and the experiment and simulated results are in good agreement with each other.
文摘Bell tests with entangled light have been performed many times in many ways using linear polarizers, but the same tests have never been done with a circular polarizer. Until recently there has never been a true circular polarization beamsplitter—an optical component that separates light directly into left and right handed polarizations. Using a true circular polarization beamsplitter based on birefringent gratings, entangled light has been analyzed with unexpected results.
基金supported by the National Natural Science Foundation of China (21988102, 52173190, and 52303257)the Ministry of Science and Technology of China (2018YFA0704803 and 2018YFA0208502)+2 种基金Youth Innovation Promotion Association CAS (2018034)Shanxi Province Science Foundation for Youths (202203021222297)project funded by China Postdoctoral Science Foundation (2023TQ0300 and 2022M721331)。
文摘Chiral two-dimensional(2D) perovskites offer numerous attractive features for optoelectronics owing to their soft, deformable lattices and a high degree of chemical tunability. While tremendous advances have been made in perovskite-based direct circularly polarized light(CPL) detection, the low circular polarization anisotropy factor and sensitivity of those photodetectors arising from large lattice distortion still limit practical applications. Herein, chiral 2D perovskite-based single-crystalline microwire arrays with enhanced circular dichroism(CD) absorption are fabricated with the synergy of the capillary-bridgeconfined assembly method and chlorine-substituted phenethylamine(Cl-MBA). Compared with phenethylamine(MBA)-inserted perovskites, the smaller lattice distortion and increased halogen–halogen interaction within Cl–MBA-inserted perovskites strengthen lattice rigidity and weaken electron–phonon coupling to improve carrier transport and thermal stability, resulting in high-performance CPL photodetectors with an anisotropy factor of 0.25, responsivity exceeding 95.7±9.3 A W^(-1)and detectivity exceeding(3.05±0.30)×10^(13)Jones. This work opens a new perspective to modulate circular polarization sensitivity and will be helpful to realize promising implementations in quantum computation and communication.