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We demonstrate high-efficient polarization insensitive OAM generation using integrated phase masks and measure their tolerance to the misalignment of incident beams. An 80 Gbit/s communication link of two OAM channels by using phase masks is demonstrated.
The generation of primary sub-comb-lines with high coherence using dual pumps in a SiN microresonator is investigated. A total capacity of 400 Gbit/s has been experimentally demonstrated in coherent communications based on the generated combs.
Line drive bionic flexible robot is a new type of robot which is based on the biological organs, such as nasal, octopus, snakes and so on. It is according to the performance principle of Chinese traditional folk drama ‘shadow play’. Recent years, it is gradually becoming a new research hotspot. In this article, it emphatically describes how to design this kind of robot and the relevant kinematics...
Based on the research of visual servo, this paper designs a set of high-speed dynamic target acquisition and processing visual system and also applies it to a servo robotic product. The experiment proves that this system had high robustness and instantaneity, which can detect and locate high-speed movement target and obtain its dynamic information, then sends data to the servo control system of the...
According to the demand of manipulator's repeatability in industrial production line, we developed a portable measurement equipment and especially designed the structure of reference block. Meanwhile, we proposed an algorithm to reduce difficulty of measurement. Then we operated a simulation experiment on manipulator through Pro/Engineer, which is abbreviated to Proe in the following text, and got...
Collaborative robots share the same workspace with humans, and it is inevitable that the robot will contact with humans or environments, so the importance of robot collision detection and end-effector contact force estimation has been receiving much attention. The conventional collision detection methods are based on extra sensors, which are not only increase cost but also increase the complexity...
This paper reports an experimental investigation of using orthogonal frequency division multiplexing (OFDM) on orbital-angular momentum (OAM) channels when there is intersymbol interference (ISI) caused by multipath effects. The impulse response measurement indicates that due to the divergence of OAM beams, channels of larger OAM number are more affected by the ISI caused the reflections from surrounding...
To identify the out-of-database targets in the process of radar ground target recognition with high resolution range profile, this paper proposes an improved radar ground target classifier based on the covariance distribution of the space of training features, namely Dual-SVDD classifier. In the training phase, a double correlate SVDD structure is constructed in feature space and a multi-region data...
The time-domain response is analyzed by precise integration method in condition of non-uniform coupled transmission lines in this paper. Different to the traditional method, this method directly analyzes it according to the non-uniformity of non-uniform transmission lines so as to avoid decoupling the coupled telegraph equations. The accuracy and speed of the analysis are improved greatly. It is a...
We experimentally demonstrate and investigate the performance of a multi-input-multiple-output (MIMO) free-space optical link employing orbital-angular-momentum multiplexing through turbulent channel. We show that turbulence effects can be mitigated by exploiting spatial diversity and MIMO equalization.
The reflection, transmission, and absorption coefficients of a dusty plasma slab at terahertz frequency are simulated using the shift operator finite-difference time-domain (SO-FDTD) method. The problem which incorporates both frequency dispersion and dust particles' contribution is solved for the electromagnetic waves propagation in dusty plasmas. The numerical verification of the approach is performed...
This paper presents a hybridized discontinuous Galerkin time-domain (DGTD) method with boundary integral equation (BIE) method to accurately solve the electromagnetic scattering problems. The weighted Laguerre polynomials are chosen as temporal entire basis functions to expand the temporal variables, which makes the proposed scheme free from Courant-Friedrichs-Lewy (CFL) condition and promising for...
Following the work of Bender et al. [1], systems with parity and time symmetry (that is, they are invariant under a mirror reflection and complex conjugation) have been extensively studied. The interesting aspect of PT-symmetric theory is to replace the traditional condition that the Hamiltonian of a quantum system must be Hermitian with the weaker condition that it combines parity and time symmetry...
Orbital Angular Momentum (OAM) has drawn great attention of worldwide academia in the recent years. It has been intensively applied in the domains of optics. Recent studies imply that OAM vortex wave can be used in radio not only limited to optics. Then, the application of OAM in radio has gradually become a research hotspot, and developing effective antennas to produce OAM beams is one of the key...
In this paper, a new multi-functional reflective polarization converter (RPC) is proposed based on an anisotropic metasurface. The metasurface is composed of the periodic array of square patches with truncated corners and a solid ground plane. The RPC is designed based on a single-layer anisotropic metasurface. The reflected magnitude and phase of the anisotropic metasurface are different in two orthogonal...
As mobile devices grew rapidly over the past few years, the wireless data demand has increased exponentially. Due to the extremely high price of licensed spectrum, License Assisted Access (LAA) has been proposed to provide high capacity by extending LTE transmissions to the unlicensed spectrum that WiFi systems operate. Due to the coexistence with WiFi systems, mobility management has become a critical...
In this paper, a reflectarray is designed to generate an orbital angular momentum (OAM) vortex wave at 0.1THz. The elements of circular patch with different radii are introduced to design the reflectarray producing an OAM wave. The simulation results implied that the OAM wave can be effectively generated by reflectarrays in THz band. The proposed method may provide a new way to generate the OAM vortex...
This paper develops a scattering cancellation technique to design a cloak for a radial inhomogeneous sphere object. The inhomogeneous spherical target is divided into many thin layers of piecewise homogeneous layers. By analyzing the scattered fields by the inhomogeneous sphere coated by an isotropic material according to Mie series theory, the geometrical dimensions and electromagnetic parameters...
To predict lower bounds on the performance of applications, the cloud should provide guarantees on bandwidth that each virtual machine can obtain. By competing for spare network bandwidth, current solutions that provide bandwidth guarantees can achieve work conservation as well. However, they usually fail to provide accurate bandwidth guarantees, for the interference between traffic for achieving...
LTE License-Assisted Access (LTE-LAA) in unlicensed spectrum has drawn a lot of attention due to its appealing data traffic offloading potential. However, the coexistence of LTE and WiFi technologies in the same unlicensed bands needs careful design to avoid severe interference between them. In this paper, we propose a coexistence scheme to create opportunities for LTE-LAA small cells and WiFi devices...
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