User:Chenjin102120

PhD focused on gradient refractive index lens including typical GRIN lens and GRIN lens antenna such as Luneburg lens, Maxwell-fisheye lens and Mikaelian lens. Research interests also cover photonic crystals, GRIN metamaterial, and transformation optics acoustics. Proficient in theoretical design of GRIN lens, corresponding structural design, and experimental nearfield, far field test of electromagnetic field. 17 Published papers, including Laser Photonics Reviews, Advanced Optical Materials, Photonics Research, IEEE Transactions on Antennas and Propagation, ACS Applied Materials and Interfaces, Physical Review Applied, Carbon, Composites Science and Technology, and Journal of Physics D: Applied Physics.

Specialties: (1) Skilled use of AutoCAD, UG, MATLAB, COMSOL and other software for structural design and simulation analysis of Metamaterial; (2) Solid understanding the theory of transformation optics and geometric optics; (3) Mastering experimental test method of near field test of Electromagnetic field, Antenna automatic measurement system

Academic Experience

Beijing Institute of Technology. | Beijing, China

Broadband all dielectric achromatic super focusing and far field magnifying lens

Enlightened by Maxwell’s fish-eye lens, a semicircular gradient solid immersion lens (GSIL) is proposed and manufactured by gradient isotropic dielectrics. Highly efficient (above 85%) achromatic (7-13GHz) super- focusing with full width at half maximum (FWHM) around 0.15λ and large NA of 2.4 as well as sub-diffraction far field radiation (4-12GHz) with high recognition have been achieved. Theoretical analysis reveals that electric field enhancement at the lens/air interface and conversion of electromagnetic (EM) wave propagation with high wave-vector in GSIL to EM wave propagation with low wave-vector in air contribute to super focusing and sub-diffraction far field radiation respectively. Measured results of near field and far field agree well with those of theoretical predictions, which makes the presented lens has the potential to be applied in super resolution imaging system. Below is the summary of this work: •	derivation of gradient refractive index distribution of semicircular GRIN lens and flat impedance matching GRIN lens to achieve super resolution are completed •	corresponding gradient periodic structure in radial direction and x direction are fully designed and manufactured by 3D printing. •	achromatic (7-13GHz) super- focusing with FWHM around 0.15λ and large NA of 2.4 as well as magnified far field radiation (4-12GHz) with high recognition have been achieved •	this work has been published in reference [2] of academic publication

Conformally Mapped Mikaelian Lens for Broadband Achromatic High Resolution Focusing

On the basis of Mikaelian lens derived from conformal transformation optics, a rectangular gradient refractive index lens with a relatively larger refractive index profile is put forward and manufactured by gradient isotropic dielectrics. Highly efficient (above 74%) broadband (7–14 GHz) achromatic high resolution focusing with FWHM around 0.2λ as well as large numerical aperture (NA) of 2.04 has been accomplished. Measured results agree well with theoretical predictions, which makes the presented lens having a great potential to be employed in high resolution imaging systems.

Below is the summary of this work •	derivation of broadband achromatic high-resolution GRIN lens by conformal transformation optic •	gradient periodic structure composed of unit cells with drilled air air holes in x direction are used to realize the deigned lens and manufactured by 3D printing. •	highly efficient (above 74%) broadband (7–14 GHz) achromatic high resolution focusing with FWHM around 0.2λ as well as large numerical aperture (NA) of 2.04 has been accomplished. •	this work has been published in reference [1] of academic publication

Ultra-broadband compact lens antenna with high performance based on a transmission gradient index medium

A gradient refractive index design strategy is proposed for a flat lens, which can transform wavefront by rectifying the local transmission phase. The designed lens is composed of two types of low-loss dielectrics with subwavelength gradient periodic structure and manufactured by 3D printing and computer-controlled machining. The measured results of the near and far field agree well with those of theoretical predictions and numerical simulations. It is demonstrated that this light-weight, low cost, compact lens antenna is highly directive (side lobes below −10 dB) and the incident plane waves are focused well with high focusing efficiency (above 80%) over an ultrabroadband frequency range with a bandwidth ratio of 138% (4–22 GHz). The demonstrated flat lens provides an alternative strategy for microwave communication, detection, and imaging applications. Below is the summary of this work •	by rectifying the local transmission phase, A gradient refractive index design strategy is proposed for a flat lens to transform wavefront. •	according to derived refractive index distribution, gradient periodic structure in x direction is designed and manufactured by 3D printing and computer-controlled machining. •	light-weight, low cost, compact, and highly directive (side lobes below −10 dB) lens antenna with high focusing efficiency is realized •	This has been published in reference [7] of academic publication

Typical GRIN lens Luneburg lens

Via designing all dielectric gradient periodic structure in radial direction by inversed Y-shaped unit cell, planar Luneburg lens is designed and manufactured by 3D printing to fulfill highly directive radiation and achromatic subwavelength focusing. Then, by rotating a two dimensional gradient periodic fully symmetrical structure, structural design of 3D Luneburg lens is also accomplished by 3D printing. Below is the summary of this work •	gradient periodic structure in radial direction structure. Planar Luneburg lens’s ability to focus electromagnetic wave and produce highly directive radiation pattern in the far field in the frequency range of 6Hz to 16GHz has been experimentally verified •	3D Luneburg lens’s highly directive and subwavelength focusing property in the frequency range of 6Hz to 20GHz is also verified •	the work about Planar Luneburg lens and 3D Luneburg lens have been published in reference [5-6, 8] and reference [3] of academic publication respectively

Xi’an Jiaotong University.| Xi’an, China

Illusion devices with complex metamaterial structures

In the Cylindrical coordinate system, composite linear transformation in the radial and angular direction is constructed to a rotatable illusion device, which can generate various illusion effects on antenna radiation pattern hinging upon the location of the radiation source.

Below is the summary of this work •	For the radiation element placed on the boundary of the external region, electromagnetic field distribution is rotated and compressed in the meanwhile •	The radiation element located in the region covering compression zone and extension zone, the radiation pattern is altered, an omnidirectional radiation is transformed into a directive one and deflected with a certain angle. •	radiation source contained in the compression zone is virtually moved to the space outside of the illusion device and rotated a certain angle as defined simultaneously •	This work has been published in reference [9] of academic publication

Directive Multiple Beam Emission Lens Formed With 2D And 3D Linear Coordinate Transformation Optics A linear coordinate transformation lens that can transform the omnidirectional radiation into reconfigurable number of highly directive beams is presented.

Below is the summary of this work •	In 2-D space, the parameters of transformed medium are homogeneous and positive, and the number of beams has no effect on parameters •	Extending this method to 3-D case, the resulting parameters become even simpler and isotropic, which leads to broadband characteristics of the designed device and the lens can be manufactured by common metamaterials and isotropic material. •	Full wave simulations are performed to validate our design. This work has published in reference [10] academic publication Education

PhD, Mechanics Beijing Institute of Technology | Beijing, China

Master of Engineering, Mechanical Engineering (MEME) Xi’an Jiaotong University |Xi’an, China

Bachelor of Engineering, Mechanical Engineering (BE) Jianghan University |Wuhan, China

Academic Publications [1] J. Chen, H. Chu, Y. Lai, Z. Liu, H. Chen, M. Chen, D. Fang, Conformally Mapped Mikaelian Lens for Broadband Achromatic High Resolution Focusing. Laser Photonic Rev. 2021, 15, 2000564.

[2] J. Chen, Y. Zhou, H. Chu, Y. Lai, H. Chen, M. Chen, D. Fang, Highly Efficient Gradient Solid Immersion Lens with Large Numerical Aperture for Broadband Achromatic Deep Subwavelength Focusing and Magnified Far field. Adv. Opt. Mater. 2021, 9, 202100509.

[3] J. Chen, X. Yuan, M. Chen, X. Cheng, A. Zhang, G. Peng, W. L. Song, D. Fang, Ultrabroadband Three-Dimensional Printed Radial Perfectly Symmetric Gradient Honeycomb All-Dielectric Dual-Directional Lightweight Planar Luneburg Lens. ACS Appl. Mater. Interfaces. 2018, 10, 38404.

[4] J. Chen, H. Chu, Y. Lai, H. Chen, W. Song, M. Chen, D. Fang, Highly Efficient Achromatic Sub-diffraction focusing lens in the Near Field with Large Numerical Aperture. Photonics Research. 2021, 9, 2088-2094

[5] J. Chen, G. Y. Su, S. H. Xu, M. J. Chen, Y. Q. Liu, D. N. Fang, J. Zhou, Ultrabroadband and Multifunctional Achromatic Mikaelian lens on an Elastic Plate. Phys. Rev. Appl. 2022, 18, 064047.

[6] J. Chen, H. Chu, Y. Zhang, Y. Lai, M. Chen, D. Fang, Modified Luneburg Lens for Achromatic Sub-Diffraction Focusing and Directional Emission. IEEE Trans. Antennas Propag 2021, 69, 7930-7934

[7] J. Chen, Y. Lin, G. Peng, Y. Huang, A. Zhang, W. L. Song, M. Chen, Z. Liu, D. Fang, An all-dielectric 3D Luneburg lens constructed by common-vertex coaxial circular cones. J. Phys. D: Appl. Phys. 2020, 53, 015110

[8] J. Chen, H. Chu, Y. Huang, Y. Lai, Z. Liu, M. Chen, D. Fang. Ultrabroadband compact lens antenna with high performance based on a transmission gradient index medium. J. Phys. D: Appl. Phys. 2021,54, 175101

[9] J. Chen, H. Chu, Y. Huang, Y. Lai, M. Chen. Ultra-Wideband Luneburg Lens with High Performance based on Gradient Metamaterials, Journal of Physics D: Applied Physics. 2022, 55,355109 [10] J. Chen, X. He, M. Chen, Y. Liu. Broadband Achromatic Flexural Wave Mikaelian Lens For High Resolution Metamaterials, Journal of Physics D: Applied Physics. 2022, 55, 335502

[11] J. Chen, M. Chen, D. Fang, Broad Terahertz Radial Perfectly Symmetric Gradient Honeycomb All-Dielectric Planar Luneburg Lens. (13th International Congress on Artificial Materials for Novel Wave Phenomena – Metamaterials 2019, EI, IEEE Xplore)

[12] J. Chen, M. Chen, D. Fang, Multifunctional rotatable illusion device. (2019 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference, EI, IEEE Xplore)

[13] J. Chen, X. Yuan, D. Fang, RECONFIGURABLE DIRECTIVE MULTIPLE BEAM EMISSIONS LENS FORMED WITH 2D AND 3D LINEAR COORDINATE TRANSFORMATION OPTICS. (2018 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference, EI, IEEE Xplore)

[14] Y. Huang, J. Chen, Q. Fan, M. Chen, D. Fang, Multifunctional carbon fiber reinforced multilayered metastructure with broadband microwave absorption and effective mechanical resistance. Polym. Compos. 2021, 42, 1846-1854.

[15] Y. Huang, Q. Fan, J. Chen, Li L, M. Chen, L. Tang, D. Fang. Optimization of flexible multilayered metastructure fabricated by dielectric-magnetic nano lossy composites with broadband microwave absorption. Compos Sci Technol. 2020, 191,108066.

[16] Y. Huang, X. Yuan, M. Chen, W. Song, J. Chen etc. Ultrathin Flexible Carbon Fiber Reinforced Hierarchical Metastructure for Broadband Microwave Absorption with Nano Lossy Composite and Multi-scale Optimization, ACS Appl. Mater. Interfaces. 2018, 10, 44731

[17] Y. Huang, X. Yuan, M. Chen, W. Song, J. Chen etc. Ultrathin Multifunctional Carbon/Glass Fiber Reinforced Lossy Lattice Metastructure for Integrated Design of Broadband Microwave Absorption and Effective Load Bearing, Carbon. 2019,144, 449.