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There were measuring errors when the inconstant currents are measured with shunts, because the skin effect increased the resistance and decreased the inductance. This paper has analyzed the circuit model of shunts with different frequency by using field-circuit coupling method and the analysis results have been validated by experiment. This paper provided a more accurate engineering method to analyze...
To rapidly capture the electromagnetic scattering behavior of electrically large and complex structures, we have developed a hybrid high frequency (HF) simulation tool through the combination of different asymptotic methods, such as physical optics (PO), shooting and bouncing rays (SBR), and physical theory of diffraction (PTD). Careful consideration of integrating PO, PTD, and SBR together ensures...
We consider the accuracy improvement of the high frequency scattered fields from the 3-D convex scatter by the Fock current and the incremental length diffraction coefficient (ILDC) technique. We propose the numerical contour deformation method to calculate the Fock currents, and treat them in the scatterer's lit and shadow regions, separately. Then, by adopting the ILDC technique, high frequency...
The Theory of Characteristic Modes (CM) provides a powerful tool of analyzing the radiators, which exhibits the orthogonality of basis radiation patterns. The properties of CM can be exploited by eigenvalues and eigenvectors solved by the general eigenvalue equation formulated from the Method of Moments impedance matrix. So the CM is parameterized by frequency, the tracking of which can reveal the...
The discontinuous Galerkin (DG) method is combined with the augmented electric field integral equation (AEFIE). AEFIE is proved to be stable in the low-frequency regime. The DG method admits non-conformal elements by using square-integrable, basis and test functions during the discretization. The resultant AEFIE-DG formulation is thus suitable solving the low frequency problems with non-conformal...
This paper summarizes recent development in efficient solution of electromagnetic problems based on integral equation. First, hybridization of integral equation method with differential equation method is introduced for reverberation chamber (RC) modeling. It is shown that the hybrid method significantly reduces computational load for RC modeling. Second, dimension reduction for efficient analysis...
In this paper, the implementation of UPML in DGTD is presented. Based on equations of UPML and the characteristics of the unstructured grid, time stepping strategy is given. The numerical results of radiation and scattering are demonstrated with good absorption of UPML in DGTD.
In this paper, the Finite-Difference Time-Domain (FDTD) method is used to simulate the near electromagnetic field when an aircraft is located on the layered half space. To solve this problem, the Π-shape Total-Field/Scattering-Field (TF-SF) boundary scheme is introduced. The 2D side TF/SF boundaries are governed by the modified 1D Maxwell's equations, and then, 3D TF/SF boundaries are projected onto...
In this paper, microwave breakdown is analyzed in arbitrarily-shaped waveguide with the help of the Spectral Element Method (SEM). Both the electromagnetic fields distributed in the structure and the free electron continuity equation are solved by the SEM. Based on such a highly accurate numerical method, both tail-erosion phenomenon in time domain and bandwidth broaden in frequency domain caused...
In this paper, a new category of waveguide E-plane filters is summarized. This kind of filters use the planar stripline as the resonating element. This kind of filters using split-block substrate insert E-plane technology can achieve very compact filtering structure at millimeter-wave with very low fabrication cost. Four different waveguide E-plane filters are presented.
A four-way compact unequal power divider is proposed in this paper. Compared to the traditional unequal power divider, the proposed circuit uses the transmission lines less than quarter wavelength to achieve desired power dividing. The analysis and general equations are presented. Finally, to demonstrate the validity of the proposed design strategies, a four-way power divider working at 1.5 GHz with...
In this paper, we propose a frequency division technique for transferring wireless powers simultaneously to two receivers. The network is composed of one transmitter and two receivers, with three matching networks to match the two loading coils to the source at two different frequencies. The application scenario and the corresponding circuit model are presented. An illustrative example is finally...
This paper presents a novel dual-mode dielectric filter, utilizing two degenerate modes, TM120 and TM210. The structure consists of a cuboid dielectric resonator short-circuited on top and bottom surface by a rectangular metallic cavity. The frequencies of resonant modes are tunable by metallic screw while modes coupling coefficient controllable by metallic ring. On this basis, we design single-cavity,...
A novel modified-design of Hilbert curve is presented, which has stable frequency response for both TE and TM polarizations. Furthermore, a frequency selective surface (FSS) based on this modified-Hilbert curve is proposed for shielding against dual-band WLAN. It has an insertion loss of more than 15 dB with the bandwidths of 220 MHz at 2.45 GHz and 160 MHz at 5.78 GHz. The proposed FSS provides an...
In this paper, the propagation characteristics of UWB (Ultra-wideband) signal in the indoor NLOS (Non-Line-of-Sight) environment are discussed based on the time-domain ray tracing method. Propagation characteristics are analyzed by considering of multipath propagation mechanisms including direct ray, reflection and transmission, such as the time-domain normalized electric field intensity, instantaneous...
In this paper, we proposed a reflector antenna array with annular parabolic trough reflecting surface for generating the orbital angular momentum modes. In this array, eight antenna elements are evenly distributed on the circular focal line of the revolutionary parabolic trough surface structure. Comparing to the array without reflecting surface and the array with conventional parabolic reflecting...
The complementary split ring resonator (CSRR) is a widely used planar metamaterial structure in the design of microstrip antennas and other microstrip elements. In this work, a study has been made on converting a single band microstrip antenna into a dual band microstrip antenna by etching a CSRR structure from the ground plane below the patch. Initially, a simulation based study of the phenomenon...
The main information of image focus in the target area, and the rest part contains a large amount of redundancy. The image segmentation is an important technology in image processing. This paper presents an improved rough set image segmentation algorithm, which is based on the theory of fuzzy C-means clustering, the human visual attention model and relative position. Combination of fuzzy clustering...
In this paper, we propose an improved quadric error metrics algorithm based on triangle strips which raises the speed of compression and keeps the features of the appearance of cultural relics well. We also establish the hierarchical model of gradual transmission, which resolves the problem of undesirable high time expenses when transmitting the artifact model. In the first place, triangle strips...
A high-power wireless LAN (WLAN) access point (AP) based on IEEE802.11n/ac standard makes it possible to build easily wireless networks including a few floors in the adjacent as well as many rooms in the same floor. This paper discusses indoor propagation characteristics including received signal strength indicators (RSSI) and channel modeling in the premises of Information Initiative Center, Hokkaido...
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