The energy crisis has aroused widespread concern, and the reform of energy structure is imminent. In the future,the energy structure will be dominated by the solar energy and other renewable energy sources. The solar ...The energy crisis has aroused widespread concern, and the reform of energy structure is imminent. In the future,the energy structure will be dominated by the solar energy and other renewable energy sources. The solar concentrating technology as a promising method has been widely studied for collecting solar energy. However, the previous solar concentrating technologies suffer from some drawbacks, such as low focusing efficiency and large concentrating size. The Luneburg lens with highly efficient aberration-free focusing provides a new route for solar/energy concentrator. In this work, we designed a plane focal surface Luneburg lens(PFSLL) by transformation optics(TO). The PFSLL provides a relatively high focusing efficiency and concentration ratio of collection of energy. At the same time, it circumvents the disadvantage of curve surface of the classical Luneburg lens in device integration. Based on the reciprocity of electromagnetic waves, the PFSLL can also be applied to the antenna field to achieve broadband wide-angle scanning and highly directional radiation.展开更多
Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss p...Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss produced by multi-beam parabolic antenna.Based on 3-D printing technique,Luneburg lens antennas by drilling holes are studied.Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials,hole shapes,hole directions,and porosity.After tests,polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength.Permittivity with the shape of triangle is the lowest due to the homogeneity.Relative permittivities with the direction at a range of 15°-45°are lower while loss tangent at a range of 0°-30°.Radial directional holes are more appropriate for Luneburg lens.The relative permittivity is decreased with the increment of porosity.After calculations,the forecasts calculated by Looyenga and A-BG theory are more precise.Finally,Luneburg lens with two layers is fabricated by 3-D printing.展开更多
In a single nanoscale device, surface plasmon polaritons(SPPs) have potential to match the different length scales associated with photonics and electronics. In this Letter, we propose an accurate design of a plasmoni...In a single nanoscale device, surface plasmon polaritons(SPPs) have potential to match the different length scales associated with photonics and electronics. In this Letter, we propose an accurate design of a plasmonic metasurface Luneburg lens(PMLL) accommodating SPPs. The simulations indicate that the full width at half-maximum is 0.42 μm, and the focus efficiency is 78%. The characters of a PMLL have robustness to manufacturing errors. The PMLL is applied in a 10 μm long compact coupler model, which couples the SPPs to the 40 nm wide output waveguide. The couple efficiency is higher than that of a conventional taper coupler in a broad bandwidth. The design is compatible with standard lithography technology.展开更多
针对目前龙伯透镜在工程应用中材料发展不成熟、质量大等问题,提出了一种质量小、性能优异的新型异形龙伯透镜天线。首先基于准保角变换法对低介电常数龙伯透镜进行压缩得到了一款高介电常数椭圆龙伯透镜,然后采用球形与椭球的特殊组合...针对目前龙伯透镜在工程应用中材料发展不成熟、质量大等问题,提出了一种质量小、性能优异的新型异形龙伯透镜天线。首先基于准保角变换法对低介电常数龙伯透镜进行压缩得到了一款高介电常数椭圆龙伯透镜,然后采用球形与椭球的特殊组合结构,得到了一款工作于X波段的高介电常数异形龙伯透镜天线。最后,利用聚二甲基硅氧烷(PDMS)和钛酸锶(Sr TiO3)陶瓷粉体混合而成的聚合物-陶瓷复合材料制备了该透镜,将制备好的聚合物-陶瓷复合材料注入3D打印的模具中来说明异形龙伯透镜的制作过程。测试结果表明,所制作的透镜天线在8.5 GHz、10 GHz、12 GHz时的最大增益值分别为20.8 d Bi、22.4 d Bi、22.6 d Bi,旁瓣电平均低于-19 d B,方位面上3 d B波束宽度小于9.8°。所提出的异形龙伯透镜具有质量轻、材料制备过程简单、制作周期短且在低温下即可无缝成型的优良特点。展开更多
The fifth generation(5G)network communication systems operate in the millimeter waves and are expected to provide a much higher data rate in the multi-gigabit range,which is impossible to achieve using current wireles...The fifth generation(5G)network communication systems operate in the millimeter waves and are expected to provide a much higher data rate in the multi-gigabit range,which is impossible to achieve using current wireless services,including the sub-6 GHz band.In this work,we briefly review several existing designs of millimeter-wave phased arrays for 5G applications,beginning with the low-profile antenna array designs that either are fixed beam or scan the beam only in one plane.We then move on to array systems that offer two-dimensional(2D)scan capability,which is highly desirable for a majority of 5G applications.Next,in the main body of the paper,we discuss two different strategies for designing scanning arrays,both of which circumvent the use of conventional phase shifters to achieve beam scanning.We note that it is highly desirable to search for alternatives to conventional phase shifters in the millimeter-wave range because legacy phase shifters are both lossy and costly;furthermore,alternatives such as active phase shifters,which include radio frequency amplifiers,are both expensive and power-hungry.Given this backdrop,we propose two different antenna systems with potential for the desired 2D scan performance in the millimeter-wave range.The first of these is a Luneburg lens,which is excited either by a 2D waveguide array or by a microstrip patch antenna array to realize 2D scan capability.Next,for second design,we turn to phased-array designs in which the conventional phase shifter is replaced by switchable PIN diodes or varactor diodes,inserted between radiating slots in a waveguide to provide the desired phase shifts for scanning.Finally,we discuss several approaches to enhance the gain of the array by modifying the conventional array configurations.We describe novel techniques for realizing both one-dimensional(1D)and 2D scans by using a reconfigurable metasurface type of panels.展开更多
基金Project supported by the National Key Research and Development Program of China (Grant No. 2020YFA0710100)the National Natural Science Foundation of China (Grant Nos. 92050102 and 11874311)+1 种基金the Shenzhen Science and Technology Program (Grant No. JCYJ20210324121610028)the Fundamental Research Funds for the Central Universities (Grant Nos. 20720220033 and 20720200074)。
文摘The energy crisis has aroused widespread concern, and the reform of energy structure is imminent. In the future,the energy structure will be dominated by the solar energy and other renewable energy sources. The solar concentrating technology as a promising method has been widely studied for collecting solar energy. However, the previous solar concentrating technologies suffer from some drawbacks, such as low focusing efficiency and large concentrating size. The Luneburg lens with highly efficient aberration-free focusing provides a new route for solar/energy concentrator. In this work, we designed a plane focal surface Luneburg lens(PFSLL) by transformation optics(TO). The PFSLL provides a relatively high focusing efficiency and concentration ratio of collection of energy. At the same time, it circumvents the disadvantage of curve surface of the classical Luneburg lens in device integration. Based on the reciprocity of electromagnetic waves, the PFSLL can also be applied to the antenna field to achieve broadband wide-angle scanning and highly directional radiation.
基金supported by the Science and Technology Programme of Shijiazhuang under Grant 151130081A
文摘Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss produced by multi-beam parabolic antenna.Based on 3-D printing technique,Luneburg lens antennas by drilling holes are studied.Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials,hole shapes,hole directions,and porosity.After tests,polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength.Permittivity with the shape of triangle is the lowest due to the homogeneity.Relative permittivities with the direction at a range of 15°-45°are lower while loss tangent at a range of 0°-30°.Radial directional holes are more appropriate for Luneburg lens.The relative permittivity is decreased with the increment of porosity.After calculations,the forecasts calculated by Looyenga and A-BG theory are more precise.Finally,Luneburg lens with two layers is fabricated by 3-D printing.
基金supported by the National Key R&D Program of China (No. 2017YFA0403400)the National Natural Science Foundation of China(No. 11775291)。
文摘In a single nanoscale device, surface plasmon polaritons(SPPs) have potential to match the different length scales associated with photonics and electronics. In this Letter, we propose an accurate design of a plasmonic metasurface Luneburg lens(PMLL) accommodating SPPs. The simulations indicate that the full width at half-maximum is 0.42 μm, and the focus efficiency is 78%. The characters of a PMLL have robustness to manufacturing errors. The PMLL is applied in a 10 μm long compact coupler model, which couples the SPPs to the 40 nm wide output waveguide. The couple efficiency is higher than that of a conventional taper coupler in a broad bandwidth. The design is compatible with standard lithography technology.
文摘针对目前龙伯透镜在工程应用中材料发展不成熟、质量大等问题,提出了一种质量小、性能优异的新型异形龙伯透镜天线。首先基于准保角变换法对低介电常数龙伯透镜进行压缩得到了一款高介电常数椭圆龙伯透镜,然后采用球形与椭球的特殊组合结构,得到了一款工作于X波段的高介电常数异形龙伯透镜天线。最后,利用聚二甲基硅氧烷(PDMS)和钛酸锶(Sr TiO3)陶瓷粉体混合而成的聚合物-陶瓷复合材料制备了该透镜,将制备好的聚合物-陶瓷复合材料注入3D打印的模具中来说明异形龙伯透镜的制作过程。测试结果表明,所制作的透镜天线在8.5 GHz、10 GHz、12 GHz时的最大增益值分别为20.8 d Bi、22.4 d Bi、22.6 d Bi,旁瓣电平均低于-19 d B,方位面上3 d B波束宽度小于9.8°。所提出的异形龙伯透镜具有质量轻、材料制备过程简单、制作周期短且在低温下即可无缝成型的优良特点。
文摘The fifth generation(5G)network communication systems operate in the millimeter waves and are expected to provide a much higher data rate in the multi-gigabit range,which is impossible to achieve using current wireless services,including the sub-6 GHz band.In this work,we briefly review several existing designs of millimeter-wave phased arrays for 5G applications,beginning with the low-profile antenna array designs that either are fixed beam or scan the beam only in one plane.We then move on to array systems that offer two-dimensional(2D)scan capability,which is highly desirable for a majority of 5G applications.Next,in the main body of the paper,we discuss two different strategies for designing scanning arrays,both of which circumvent the use of conventional phase shifters to achieve beam scanning.We note that it is highly desirable to search for alternatives to conventional phase shifters in the millimeter-wave range because legacy phase shifters are both lossy and costly;furthermore,alternatives such as active phase shifters,which include radio frequency amplifiers,are both expensive and power-hungry.Given this backdrop,we propose two different antenna systems with potential for the desired 2D scan performance in the millimeter-wave range.The first of these is a Luneburg lens,which is excited either by a 2D waveguide array or by a microstrip patch antenna array to realize 2D scan capability.Next,for second design,we turn to phased-array designs in which the conventional phase shifter is replaced by switchable PIN diodes or varactor diodes,inserted between radiating slots in a waveguide to provide the desired phase shifts for scanning.Finally,we discuss several approaches to enhance the gain of the array by modifying the conventional array configurations.We describe novel techniques for realizing both one-dimensional(1D)and 2D scans by using a reconfigurable metasurface type of panels.
