The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Inseop Yoon - One of the best experts on this subject based on the ideXlab platform.
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WCNC Workshops - Polarization Dependent Beam Steerable Thin Lens Employing Spatial Filter Arrays
2020 IEEE Wireless Communications and Networking Conference Workshops (WCNCW), 2020Co-Authors: Yeongmyeong Park, Inseop YoonAbstract:This paper presents Thin Lens (
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Affordable Thin Lens Using Single Polarized Disparate Filter Arrays for Beyond 5G toward 6G
Sensors, 2019Co-Authors: Inseop Yoon, Seongwoog Oh, Jungsuek OhAbstract:This paper proposes a novel design approach for a Thin Lens with the aim of overcoming fineness limits in the commercial millimeter wave printed circuit board (PCB) manufacturing process. The PCB manufacturing process typically does not allow the fabrication of metallic patterns with a gap and width of less than 100 μm. This hampers expanding Thin Lens technology to 5G commercial applications, especially when such technology is considered for 60 GHz or higher frequency, which requires a finer gap and width of metallic traces. This paper proposes that problematic process conditions can be mitigated when a Lens is designed by establishing single-polarized lumped element models where larger capacitance and inductance values can be obtained for the same patch and grid unit cells. While the proposed design technique is more advantageous at higher target frequencies, a 60 GHz application and a wireless backhaul system is selected because of a limited range of frequencies that can be measured by an available vector network analyzer. The required gap or width of metallic traces can be widened significantly by using the proposed single-polarized unit cells to acquire the same in-plane capacitance or inductance. This enables the Lens operating at higher-frequency under the process limits in fabricable fine traces. Finally, the effectiveness of the simulated design procedure is demonstrated by fabricating a 60 GHz Thin Lens that can achieve a gain enhancement of 16 dB for a 4 × 4 patch antenna array with a gain of 16.5 dBi.
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millimeter wave Thin Lens using multi patch incorporated unit cells for polarization dependent beam shaping
IEEE Access, 2019Co-Authors: Inseop YoonAbstract:This paper describes a millimeter-wave Thin Lens that exhibits different beam-shaping characteristics depending on the polarization of the incident waves. The proposed unit cell topologies, which use multiple rectangular patches and rectangular-slotted grids, enable Thinner (= 0.05λ 0 ) and smaller (= 0.168λ 0 ) features than in previous polarization-dependent Lenses. An appropriate set of the proposed unit cells is shown to cover a tunable phase range of 180° with respect to one polarized wave but have an almost-zero tunable range of phase shifts with respect to another polarized wave. Thus, using this unit cell set for x-polarized incident waves, the proposed Lens operates as a convex Lens, whereas for y-polarized incident waves, the Lens operates as a frequency selective surface. This confirms that gain variations of 13 dB or more can be differentiated according to the polarization of the incident waves on the Lens, supporting polarization-dependent beam-shaping capability as a function of the polarization of incident waves.
Shugo Michikoshi - One of the best experts on this subject based on the ideXlab platform.
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Wave propagation in a weak gravitational field and the validity of the Thin Lens approximation
Physical Review D, 2005Co-Authors: Teruaki Suyama, Ryuichi Takahashi, Shugo MichikoshiAbstract:Wave effects can be important for the gravitational Lensing of gravitational waves. In such a case, wave optics must be used instead of geometric optics. We consider a plane wave entering a Lens object and solve numerically the wave equation for three Lens models: the uniform density sphere, the singular isothermal sphere, and the Hernquist model. By comparing our numerical solutions with the analytical solutions under the Thin Lens approximation, we evaluate the error of this approximation. The results show that the relative error of the Thin Lens approximation is small if the geometrical thickness of the Lens is much smaller than the distance between the Lens and the observer.
Jungsuek Oh - One of the best experts on this subject based on the ideXlab platform.
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Affordable Thin Lens Using Single Polarized Disparate Filter Arrays for Beyond 5G toward 6G
Sensors, 2019Co-Authors: Inseop Yoon, Seongwoog Oh, Jungsuek OhAbstract:This paper proposes a novel design approach for a Thin Lens with the aim of overcoming fineness limits in the commercial millimeter wave printed circuit board (PCB) manufacturing process. The PCB manufacturing process typically does not allow the fabrication of metallic patterns with a gap and width of less than 100 μm. This hampers expanding Thin Lens technology to 5G commercial applications, especially when such technology is considered for 60 GHz or higher frequency, which requires a finer gap and width of metallic traces. This paper proposes that problematic process conditions can be mitigated when a Lens is designed by establishing single-polarized lumped element models where larger capacitance and inductance values can be obtained for the same patch and grid unit cells. While the proposed design technique is more advantageous at higher target frequencies, a 60 GHz application and a wireless backhaul system is selected because of a limited range of frequencies that can be measured by an available vector network analyzer. The required gap or width of metallic traces can be widened significantly by using the proposed single-polarized unit cells to acquire the same in-plane capacitance or inductance. This enables the Lens operating at higher-frequency under the process limits in fabricable fine traces. Finally, the effectiveness of the simulated design procedure is demonstrated by fabricating a 60 GHz Thin Lens that can achieve a gain enhancement of 16 dB for a 4 × 4 patch antenna array with a gain of 16.5 dBi.
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Millimeter-Wave Thin Lens Employing Mixed-Order Elliptic Filter Arrays
IEEE Transactions on Antennas and Propagation, 2016Co-Authors: Jungsuek OhAbstract:This communication presents a novel approach for designing a simplified and cost-effective millimeter-wave Thin Lens by reducing the number of substrates and metal layers for a given tunable range of the phase shift. It is demonstrated that this can be achieved by employing mixed-order elliptic filter arrays where the different orders of the filter are responsible for different tunable ranges of the phase shift. The key features of the elliptic filters and their mixed-order array are introduced. It is found that constructively utilizing the interlayer coupling between the metal layers renders an elliptic filter response, and the mixed-order configuration of the elliptic filter array can be utilized to design the devised Thin Lens. The design procedure for the affordable Thin Lens configuration is discussed. The empirical and simulated results demonstrate that the conventional planar Lens can be further simplified in terms of the number of substrates and metal layers, maintaining the tunable range of the phase shift. It is confirmed that the fabricated mixed-order Lens is less than 0.05 $\lambda 0$ in total thickness and has a gain of up to 12 dB with $f/D = 0.7$ .
Teruaki Suyama - One of the best experts on this subject based on the ideXlab platform.
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Wave propagation in a weak gravitational field and the validity of the Thin Lens approximation
Physical Review D, 2005Co-Authors: Teruaki Suyama, Ryuichi Takahashi, Shugo MichikoshiAbstract:Wave effects can be important for the gravitational Lensing of gravitational waves. In such a case, wave optics must be used instead of geometric optics. We consider a plane wave entering a Lens object and solve numerically the wave equation for three Lens models: the uniform density sphere, the singular isothermal sphere, and the Hernquist model. By comparing our numerical solutions with the analytical solutions under the Thin Lens approximation, we evaluate the error of this approximation. The results show that the relative error of the Thin Lens approximation is small if the geometrical thickness of the Lens is much smaller than the distance between the Lens and the observer.
Darshan Chalise - One of the best experts on this subject based on the ideXlab platform.
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investigation of the limits of the Lens maker s formula using an experimentally verified mathematical model to determine the focal point of a convex Lens for arbitrary angle of incidence
Optik, 2019Co-Authors: Sanjana Choudhary, Darshan ChaliseAbstract:Abstract While several studies have presented experimental research and simulations in tracking the focal point, a closed form mathematical model to understand the movement of the focal point of a convex Lens when light is incident at an arbitrary angle is missing. Such closed form mathematical solutions allow significantly faster computation than numerical simulations. In addition, they provide significant physical insights that cannot be obtained from simulations or experiments. This work presents a closed form mathematical solution based on analytic geometry for calculating the position of the focal point of a convex Lens at an arbitrary Lens orientation and arbitrary angle of incidence. Results obtained from this method are verified using Lens Maker’s formula for Thin Lenses. The theoretical model presented here also agrees well with the experimental results. The verified method is then used to determine the criteria for the validity of Thin Lens approximation. As a consequence, the paper presents an explicit requirement on the radius of curvature of the Lens in terms of its length, refractive index and four dimensionless constants for Thin Lens approximation to be applicable.
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Investigation of the limits of the Lens Maker’s formula using an experimentally verified mathematical model to determine the focal point of a convex Lens for arbitrary angle of incidence
Optik, 2019Co-Authors: Sanjana Choudhary, Darshan ChaliseAbstract:Abstract While several studies have presented experimental research and simulations in tracking the focal point, a closed form mathematical model to understand the movement of the focal point of a convex Lens when light is incident at an arbitrary angle is missing. Such closed form mathematical solutions allow significantly faster computation than numerical simulations. In addition, they provide significant physical insights that cannot be obtained from simulations or experiments. This work presents a closed form mathematical solution based on analytic geometry for calculating the position of the focal point of a convex Lens at an arbitrary Lens orientation and arbitrary angle of incidence. Results obtained from this method are verified using Lens Maker’s formula for Thin Lenses. The theoretical model presented here also agrees well with the experimental results. The verified method is then used to determine the criteria for the validity of Thin Lens approximation. As a consequence, the paper presents an explicit requirement on the radius of curvature of the Lens in terms of its length, refractive index and four dimensionless constants for Thin Lens approximation to be applicable.