- 标题
- 摘要
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- 实验方案
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Generalized Friis Transmission Equation for Orbital Angular Momentum (OAM) Radios
摘要： Generalization of a Friis transmission equation for orbital angular momentum (OAM) radios is rigorously formulated using the Lorentz reciprocity theorem and a near-and-far-field convolution integral (NFCI). Based on the discretization of NFCIs, we computed the generalized Friis transmission equation to obtain the power-receiving behaviors of practical helicoidal parabolic reflector antennas (HPRAs) with continuously deformed surfaces. A simplified Friis equation is also used for computing the link budget and approximate Rayleigh length of discrete uniform circular arrays (UCAs) composed of 2×2 dipole antennas. The transmission coefficients for the given OAM modes, represented by our equations for the HPRA and UCA, agree very well with commercial numerical simulators. In addition, an mth-order NFCI, which is an orthogonal convolution integral for the mth OAM mode, is proposed to define a figure of merit for the OAM mode purity of transmitting and receiving antennas.
关键词： antenna arrays,transmitting antennas,receiving antennas,Electromagnetic propagation,reflector antennas,reciprocity principle
更新于2025-09-23 15:22:29
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On Geometric Optics over a Spherical Earth With an Exponential Refraction Index
摘要： The ray based method of geometrical optics can be used for wave propagation a over spherical earth with good results. A previous such a method also includes an exponential refraction index. This method gives good results for large terminal heights and distances, but for small distances, it has some shortcomings. In this paper, an improvement is proposed which remove these shortcomings. Also, as the method depends on numerical procedures, some improved numerical calculations are put forward.
关键词： refraction,geometrical optics,Electromagnetic propagation
更新于2025-09-23 15:21:21
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The Application of Least-Squares Finite Element Method to Simulate Wave Propagation in Bianisotropic Media
摘要： The finite element method (FEM) has been one of the major numerical techniques for electromagnetics (EM) ever since the introduction of the spurious-free edge element. On the other hand, a so-called least-squares finite element method (LSFEM) is becoming increasingly popular due to its unique properties. For instance, the generated stiffness matrix is positive definite. Effort has been made to apply this node-element-based LSFEM to model EM problems, mostly in the theoretical aspect. In this paper, we will use normalized Maxwell’s equations incorporated with the constitutive relations of bianisotropic media, which represents the most general cases in the linear regime. Subsequently, the corresponding variational formulation is derived, followed by the generation of matrix systems. We then implement and validate various boundary conditions. Further we apply this scheme to simulate wave scattering in the presence of bianisotropic media that are categorized into 3 types. A good convergence rate and agreement between the LSFEM results and the referenced solutions has been achieved, which proves the Lagrange-element-based LSFEM as a feasible alternative to the edge-element-based FEM currently used in EM modeling.
关键词： Electromagnetic metamaterials,Electromagnetic propagation,Finite element analysis
更新于2025-09-19 17:15:36
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[IEEE 2018 International Conference on Electronics, Control, Optimization and Computer Science (ICECOCS) - Kenitra, Morocco (2018.12.5-2018.12.6)] 2018 International Conference on Electronics, Control, Optimization and Computer Science (ICECOCS) - Agent based simulation of electromagnetic waves propagation using the FDTD method
摘要： In recent years, multi-agent systems have taken an increasingly important place in computer science, whether in the field of artificial intelligence, distributed systems, robotics, or even in the environmental sciences, offering the opportunity to directly represent individuals, their behaviors and their interactions. The objective of this paper is the application of the techniques of the multi-agent approach in the simulation of the propagation of electromagnetic waves by FDTD method using Netlogo.
关键词： Electromagnetic,Propagation,FDTD,Multi-agents
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO) - Reykjavik, Iceland (2018.8.8-2018.8.10)] 2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO) - Concept of a Complex Envelope Faber Polynomial Approach for the Solution of Maxwell’s Equations
摘要： We investigate a novel complex envelope approach for the numerical solution of Maxwell’s equations based on the time domain propagator using Faber the expansion of polynomials. Due to the application of the complex envelope only the envelope of the investigated fields has to be simulated. This offers promising prospects with respect to the application of larger time steps. The properties of the Faber polynomials enable a flexible and a highly accurate approximation of the time domain propagator what offers interesting prospects for the analysis of devices in the fields of THz technology and photonics.
关键词： Electromagnetic propagation,finite-difference time-domain (FDTD) methods
更新于2025-09-11 14:15:04
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Wave Propagation Concepts for Near-Future Telecommunication Systems || A Rain Estimation System Based on Electromagnetic Propagation Models and DVB-S Opportunistic Sensors
摘要： Weather conditions have in general huge impact on the global economy, in particular on agriculture, industry, transport, and so forth. In recent years, also the occurrences of rapid and localized heavy rainfall in complex topographic areas became more frequent, possibly due to global warming. These facts cause injuries and deaths, and an accurate and early alert system is required to warn people and operators. In this chapter, we describe a real-time and low-cost system for precipitation detection, aimed at collecting additional data with respect to those obtainable from traditional sensors. Such a system is based on the opportunistic usage of satellite digital video broadcasting (DVB-S) micro-wave signals and estimates the rain intensity from the detected attenuation. Our system proved to accurately obtain results comparable with rain gauges located in the experi-mentation area, with much tighter spatial and temporal scales than traditional schemes.
关键词： nowcasting,antennas,electronic circuits,electromagnetic propagation,rainfall estimation
更新于2025-09-09 09:28:46
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - Towards Performance Optimisation of the FDTD Method via Matrix Casting Approach
摘要： This publication presents matrix casting approach for the FDTD method. Applied in 2D and 3D dimensions it is subsequently parallelised with OpenMP and tested in basic air-filled and realistic landmine-detection scenarios.
关键词： performance analysis,finite difference methods,numerical simulation,electromagnetic propagation
更新于2025-09-04 15:30:14