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In this paper, we study the mode perturbations of a planar ring resonator for proposal and unified design of wideband and multiband microwave bandpass filters. Compared to a planar quarter-/half-wavelength transmission line resonator, a one-wavelength resonator based on a closed ring structure owns two orthogonal degenerate modes. By introducing a small perturbation along a ring, the two degenerate...
For the IC chips and microelectronic packaging structures, the mesh size of the objects after discretization is usually much smaller than the operating wavelength. Hence, many low-frequency full-wave engines were proposed to simulate this kind of structures with tiny meshes, which can solve the wideband problems from DC to microwave frequencies. An augmented electric field integral equation (A-EFIE)...
Electromagnetic scattering by perfect electrically conducting (PEC) objects in a layered medium is studied in this paper. The layered medium Green's function is adopted as the kernel of the electric field integral equation (EFIE) so that the effects from the multilayered background can be accounted for automatically. However, the spectrum of the EFIE with this kernel, is unfortunately undesirable...
In this paper, a full-wave semi-analytical solution of self and mutual impedances for a coil-based system is proposed. It consists of two concentric circular coils with rectangular cross sections. Traditionally, the calculation of self and mutual impedances of these coils are based on eddy current approximation, where a simple background is assumed to achieve analytical and semi-analytical solutions...
In this paper, we apply the fast Fourier transform on the perturbation-based augmented electric field integral equation (A-EFIE). The main idea lies on the Lagrangian interpolation of a series Rn, n = −1, 0, 1, 2, …, obtained by expanding Green's function using Taylor series. By utilizing the Toeplitz property of the Rn on the uniform cartesian grids, the multiplication of expanded kernels in the...
In this paper, a wideband Butler matrix based on the 3-dB cross-slotted patch hybrid couplers and interdigital coupled-line section is presented. After loading a tight-coupled-line section at each port of the coupler, the operating bandwidth is enhanced with one more transmission pole. The Butler matrix is first designed and implemented at 2.65 GHz, with about 36% −10dB return loss bandwidth. Amplitude...
In this paper, the late time stability is studied for marching on-in-time scheme in the time domain integral equation. First, the numerical evaluation of the convolution between retarded potential and time basis function is employed to ensure the accuracy. Then, we solve the first few time steps' current coefficients as eigenvectors to derive the remaining coefficients. By projecting the system onto...
Compact antenna arrays are widely investigated in modern communication technologies. In this paper, a conceptual study of compact monopole arrays used for beamforming applications is performed. Theoretical backgrounds for the design are discussed. A three-element compact monopole array with around 0.2λ0 (λ0 is the wavelength in free space) spacing operating at 2.4 GHz is modeled and simulated. Good...
Electromagnetic scattering by dielectric objects in the presence of a layered medium is investigated by applying the Poggio-Miller-Chang-Harrington-Wu-Tsai (PMCHWT) equation combined with the layered medium Green's function. Due to the electric field integral equation (EFIE) operator involved, the spectrum of the PMCHWT equation is also undesired. When the surface is densely discretized, the condition...
In this paper, a dual-basis testing method is utilized to enhance the field projection in the equivalence principle algorithm (EPA). Due to the presence of identity operators in the EPA formulation, the near-field calculation is less accurate with field projection errors. This issue can be effectively remedied by using the recently proposed dual-basis function of Rao-Wilton-Glisson basis function,...
A terminal guidance law with impact angle constrained is designed to intercept maneuvering targets in this paper. Firstly, the sliding mode guidance law is put forward on the premise of autopilot with ideal dynamic delay. The convergence property within finite time is demonstrated. Furthermore, the guidance law is extended using nonlinear backstepping method in the case of dynamics delay of autopilot...
For medical staffs, ICU is a high-risk and high-demanding environment. To reduce the medical staff's workload and improve their efficiency, we propose a user-centered approach for next generation ICU system development. The user-centered approach contains four phases: (1) user problem exploration; (2) user needs and requirements identification; (3) human-machine interface solution generation; and...
A heterogeneous network (HetNet) with macro base stations (BSs) together with low power small cells, such as pico BSs and femto BSs, is a promising solution to enhance network capacity. In HetNet, the transmission range of pico BSs are limited due to the large transmission power difference between macro and pico BSs, and thus pico BSs are typically underutilized. Cell Range Expansion (CRE) is a way...
A miniaturized antenna with circular polarization and directional pattern is presented in this paper. The conventional ground plane is replaced by a rectangular ring reflector to form the directional pattern. Since the side length of the ring reflector is around quarter-wavelength, the total size of the proposed antenna is reduced dramatically, which is about λg/2 × λg/2 in the horizontal plane. In...
In this paper, the wireless power transfer system based on magnetic-coupled resonators is modeled and optimized by using low-frequency integral equation solver. For the low-frequency transfer system, the mesh size after discretization is usually much smaller than the wavelength. Hence, the low-frequency solvers are proposed to model this kind of structures with tiny meshes. After the spiral resonators...
In this paper, the wireless power transfer link with metallic plates is studied. By enforcing the boundary conditions along metallic surface, the magnetic fields are well confined between two plates and its flux focusing can be also improved. Meanwhile, the large metallic plates can also help to achieve higher transfer efficiency of the wireless power transfer link. Based on the filter theory, these...
Clinical records are the firsthand and vital evidences for Traditional Chinese Medicine (TCM) research. With deep Chinese culture background and years of clinical experience, a TCM clinical expert usually has his or her unique diagnostic methods. Preserving clinical cases of high-experienced TCM practitioners in their original tastes and exploring the in-depth knowledge is thus an important but arduous...
With the wildly use of heterogeneous security devices like firewalls and intrusion detection systems generates huge amounts of unreliable security events, which are difficult to manage, united platform of network security management is proposed. Using risk assessment and alerts correlation, the platform can analyze the risk of network in real-time, and reduce false positive ratio and false negative...
A control system, using a TMS320F28035 as the main control chip, for a sinusoidal wave BLDC motor in applications of range hoods is proposed to realize speed automations, noise reductions and energy efficient usages. In the proposed control system, the control module of BLDC motors is based on an IPM intelligent system, and the software based on sinusoidal wave controlled SVPWM. An anti-saturation...
Traditional equivalent source reconstruction methods are only operating at a single frequency point each time. However, for wide band radiators, their computation cost of the source reconstruction increases linearly with the number of frequency points. In this paper, a wide-band equivalent source reconstruction method (WB-SRM) based on the Neville-type Stoer-Bulirsch (SB) algorithm is developed. Supported...
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