Adaptive cross approximation (ACA) algorithm as a kind of common matrix compression method is often used to analyze the electromagnetic radiation and scattering problems. In the region of far field, the impedance matr...
详细信息
ISBN:
(纸本)9781467317993
Adaptive cross approximation (ACA) algorithm as a kind of common matrix compression method is often used to analyze the electromagnetic radiation and scattering problems. In the region of far field, the impedance matrix is compressed by ACA method, and the extracted impedance matrix is accelerated filling by equivalent dipole-moment method (EDM). In the area of near field, the method of moments or the equivalent dipole-moment method is applied for filling the impedance matrix. The iterative near field preconditioning technique is used to solve matrix equation, so that fast calculation of radar cross section (RCS) can be achieved. Numerical results show that the computational efficiency is improved significantly via applying the presented method in this paper without sacrificing much accuracy.
In recent years, WSN (Wireless Sensor Network) technology has been developed rapidly, and been widely used in the fields of industry, agriculture, medicine and so on. To solve the low communication rate and short-dist...
详细信息
ISBN:
(纸本)9781467344999
In recent years, WSN (Wireless Sensor Network) technology has been developed rapidly, and been widely used in the fields of industry, agriculture, medicine and so on. To solve the low communication rate and short-distance data transmission in the current temperature and humidity monitoring system, this paper designs a temperature and humidity remote monitoring system based on WSN technology. In this system, microprocessor Atmega128L is adopted as the control core of network node, and wireless transceiver module nRF905 is used to realize wireless data transmission. The data of temperature and humidity is sampled by using digital temperature sensor DS18B20 and humidity sensor SHT75 in the system. The proposed network protocol in this paper not only can realize long-rang wireless data transmission, but also can realize self-organizing and manual networking. The results of practical test show that this system has the stable and reliable performance and the advantage of scalability.
In the theory of compressive sensing, the selection of the basis functions directly affects the sparse transformation, observation number and reconstruction accuracy. In this paper, we introduce the structure of three...
详细信息
The conventional differential space-frequency codes (DSFC) based on cyclic delay diversity (CDD) only could achieve the same transmission rate with that of a single transmit antenna system, the spectral efficiency was...
详细信息
In this paper, Maxwell's equations are taken as a Hamiltonian system and then written as Hamiltonian canonical equations by using the functional variation method. The symplectic and ADI schemes, which can be extra...
详细信息
In this paper, Maxwell's equations are taken as a Hamiltonian system and then written as Hamiltonian canonical equations by using the functional variation method. The symplectic and ADI schemes, which can be extracted by applying two types of approximation to the time evolution operator, are explicit and implicit scheme in computational electromagnetic simulation, respectively. Since Finite-difference time-domain (FDTD) encounter low accuracy and high dispersion, the more accurate simulation methods can be derived by evaluating the curl operator in the spatial direction with kinds of high order approaches including high order staggered difference, compact finite difference and scaling function approximations. The numerical dispersion of the symplectic and ADI schemes combining with the three high order spatial difference approximations have been analyzed. It has been shown that symplectic scheme combining with compact finite difference and ADI scheme combining with scaling function performance better than other methods. Both schemes can be usefully employed for simulating and solving the large scale electromagnetic problems.
The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor tar...
详细信息
ISBN:
(纸本)9781467317993
The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor targets over a broad frequency band. The FDM, which is based on the equivalent dipole-moment (EDM) method, is employed to reduce impedance matrix storage and accelerate the matrix-vector multiplications in the solutions of the Taylor coefficients. The application of AWE technique enables fast frequency sweep analysis. The numerical results show that this method greatly increased the computational efficiency without losing accuracy conditions compared with the traditional method of moments (MoM) combined with AWE technique.
An analytical solution is presented to compute the field distribution near a chiral cylinder surface at normal incidence of an on-axis Gaussian beam. The theoretical analysis of the scattering problem is complicated d...
详细信息
ISBN:
(纸本)9781467317993
An analytical solution is presented to compute the field distribution near a chiral cylinder surface at normal incidence of an on-axis Gaussian beam. The theoretical analysis of the scattering problem is complicated due to the fact that the left and right circularly polarized waves propagate in the chiral medium with different propagation constants. Numerical results for the normalized near-surface field intensity are given and discussed concisely.
The TD-SCDMA relay (repeater) provide network operators with a cost-effective means of extending coverage to areas of low signal strength. The maximum gain of a TD-SCDMA repeater is, however, limited by the amount of ...
详细信息
ISBN:
(纸本)9781467317993
The TD-SCDMA relay (repeater) provide network operators with a cost-effective means of extending coverage to areas of low signal strength. The maximum gain of a TD-SCDMA repeater is, however, limited by the amount of isolation that exists between the donor and coverage antennas. The radio echoes from coverage antennas not only create interference in the incoming signal from the base station, but also cause instability of the repeater. In this paper, we present an interference cancellation system (ICS) for TD-SCDMA networks, which can eliminate these problems. Various characteristic features of the ICS are illustrated using the MATlab simulation results.
Fast Fourier Transform (FFT) is a well known and widely used tool in many scientific and engineering fields. CUFFT, which is the NVIDIA's FFT library included in the CUDA toolkit, supports double precision FFTs. H...
详细信息
Clear image stitching becomes mature now, but how to stitch blurred images with clear ones is still tough, mainly because of the ill-posed image deblurring. Existing deblurring methods assume spatial-invarint blur ker...
详细信息
暂无评论