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Due to the energy limitation of sensor nodes, energy efficiency is one of the main concerns in the design of wireless body area networks (WBANs). Power control plays an important role in reducing network interference and resource management in WBANs. The task of power control is to achieve a certain goal by making use of smaller and suitable power transmission, which depends on the application and...
Electromagnetic fields in gyrotropic anisotropic spherical shell can be expressed as the addition of the first and second spherical vector wave functions in gyrotropic anisotropic medium. Applying the boundary conditions of electromagnetic fields in the interface of gyrotropic anisotropic spherical shell's medium, the expansion coefficients of electromagnetic fields in terms of spherical vector wave...
The paper has proposed a low-profile broadband UHF base station antenna based on lumped-element matching network with the combination of a height compressed conical antenna and a matching network. The proposed antenna is applied in base station communication systems with the frequency range from 300MHz to 870MHz. Compared with the traditional UHF base station antenna, the proposed antenna has a lower...
This paper presents a new design and optimization method of wideband printed slot antenna using a shape blending algorithm. The proposed printed antenna consists of a wide rectangular slot and a tuning stub, which is formed by the shape blending result from a pie and a diamond shape. The method is used to design a printed wide slot antenna for applications in WLAN, WiMAX and UWB. The impact of the...
In order to further detect underwater targets, such as oil, gas, and shipboard equipment and so on, we discuss the underwater radiation fields of a magnetic dipole array with 3×3 elements in the TSS-FDTD method. Numerical results show that the Hz and Ez amplitude and phase snapshots are symmetrical related to the z axis in the yoz plane in the working frequency f=180Hz. By analyzing the radiated fields,...
The echo of target with micro-motion contains the electromagnetic scattering characteristics and movement characteristics, which plays important roles in the target identification. Precession period is one of the important characteristics on the analysis of the micro-motion characteristics. Aimed at the phenomenon of extracting the cycle of no precession target, in the thesis a method is proposed...
In this paper, based on electromagnetic theory and multi-conductor transmission lines(MTL) theory, proposes a quick measurement method of the terminal equivalent impedance for multiple parallel cable-bundles. According to the method, the multiple cable-bundles are treated as equivalent of MTL firstly. After that, using vector network analyzer(VNA) and current probe measures broadband voltage reflection...
The investigation into the effect of the wind turbines (WTs) on the radar system is increasing with the growing demands for wind farms. In order to evaluate the Doppler spectrum features of the rotational WT, a simplified WT model with high reliability is proposed and the simulation results are conducted in this paper. Then the Doppler effect under different characteristics are also analyzed by utilizing...
This paper aims at simulating the multipath effect of EM scattering from low altitude target above large scale complex ocean surface. The complexity is reflected by the composite description of both large scale profile and small roughness structures of the ocean surface model. The scattering from ocean surface is calculated by a Modified Facet-based Two Scale Model. The model decomposed ocean surface...
This paper addresses a noncontact measurement application of customized signal processing using the impulse radio ultra-wideband (IR-UWB) radar to realize the rotational speed detection. Microwave radar technology offers a noncontact, quick, accurate technique and has potential for industrial applications. We studied the effect of suppression to remove the stationary background clutter, and separated...
A dual-band combined Mic-Dip antenna (Microstrip antenna and Dipole antenna) is proposed in this paper. The combined antenna, including the microstip antenna and the dipole antenna, is working for lower and upper band, respectively. To widen impedance bandwidth for the two operation bands, the coupling feed is employed for Mic-Dip antenna, which can achieve operating bandwidth of about 9.14 % ranging...
The generation mechanism of harmonic and spurious emission in the phased array radar transmitting channels are analyzed. The channels components' influence on the phase of the harmonic and spurious emission are presented. The phase of harmonic and spurious emission at the stimulating ports of antenna elements are presented as well. The beam direction of harmonic and spurious emission in line array...
SAR echo simulator plays an important role in space-borne SAR development. As it uses a wide signal bandwidth, the LFM signal is affected in the transmit and receive channel because of the non-linear characteristics. This paper focuses on the LFM signal channel pre-distortion compensation in the SAR echo simulator, and the concrete implementation steps in time-domain compensation are given. This proposed...
In this paper, we proposed an interference alignment algorithm named Robust Weighted Minimum Mean Square Error(R-WMMSE) algorithm. We also design a 3-user wireless communication system which considers realization factors to evaluate the performance of the R-WMMSE algorithm. The system is realized through a system level simulation, both in floated-point and fixed-point manner. The results suggest that...
This paper firstly introduces elementary knowledge of bio-electromagnetic dose, and then elaborates on the method and steps of theoretical bio-electromagnetic dose used to compute the electromagnetic dose absorbed by human body at the frequency 300MHz and 3GHz. Afterwards, the finite-difference time-domain (FDTD) method is utilized to analyze the dielectric property and calculate the specific absorption...
The analytical theory for the scattering of a uniaxial anisotropic illuminated by a Laguerre-Gaussian vortex beam is presented. Based on the complex source point method and the relation between Hermite polynomial and Laguerre polynomial, the expansion of Laguerre-Gaussian vortex beam expanded in terms of spherical vector wave functions is derived. Using the continuous boundary condition at the surface...
A method for modeling of graphene sheets using finite-difference time-domain method based on Laplace transform current density convolution (LTJEC-FDTD) has been proposed. The modeling of graphene sheets is achieved by obtaining recursive Maxwell's equations of tangential electric field components on graphene and current density using LTJEC. The proposed numerical formulation is compared with analytical...
For the first time, we use the nonlocal boundary conditions in wide-angle finite difference parabolic equation model to calculate the propagation loss in complex environment. The great advantage of this method is that it has less amount of calculation without any loss of accuracy. The correctness and accuracy of this method are proved by using it to compute some propagation examples.
The finite-difference time domain (FDTD), a numerical method, is an accurate approach to calculate the electromagnetic scattering coefficients of target and rough surface. However, it is very time-consuming to solve the problem for FDTD executing on a single CPU. We develop the CUDA-based parallel FDTD to accelerate the computation of electromagnetic scattering from a three-dimensional target and...
Based on the Weaver's model and Neumann ocean waves spectrum, the three-dimensional space of the three-dimensional random waves and three-dimensional model of the magnetic field generated by water movement are simulated in this paper. This paper provides a weak magnetic field reference model for the magnetic detection of long distance underwater magnetic object.
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