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For obtaining dual-polarization, using a square annular cavity in the ground plane of a broadband microstrip patch antenna, with proximity-coupling as the feeding mechanism, is proposed in this paper. The antenna has four sequentially arranged feed-lines, and each pair of opposite feed-lines in the same direction are excited by antiphase, which provides the high isolation between the two pairs of...
A broadband microstrip patch antenna with dual-polarization is presented in the paper. There are four feed-lines and a cavity-backed ground plane in the antenna. The patch is electromagnetically coupled by these feed-lines. The phase offset of the two feeding ports located symmetrically relative to the center of the patch is 180º, which affords a solution to improve the polarization purity and the...
A broadband proximity-coupled stacked patches antenna with backed cavity which has the low sensitivity of fabrication errors is presented. By adding two copper strips on the reverse side of the feed-line, the influence of the relative displacement between the feed layers and the cavity on the bandwidth performance of the antenna can be reduced. With this method, the antenna can bear the relatively...
In this study, based on the total coliforms (TC) and total bacteria (TB) detected in rural drinking water resources (RDWR) of Ya'an, and applying exponential model and β-Poisson model of “low microbe content risk assessment”, the quantitative evaluation of risk associated with TC count and TB in 221 water samples was developed. Results showed the annual risk values (ARV) of all the water samples were...
A normalized RC-FDTD algorithm is applied to study both the bistatic and monostatic radar scattering of perfectly conducting sphere covered with inhomogeneous unmagnetized plasma. The effects of electron density distributions and plasma collision frequencies on the radar cross section (RCS) are discussed respectively. The simulations confirm that plasma cladding can be successfully used to reduce...
A novel printed ultra-wideband (UWB) monopole antenna fed by coaxial cable is presented with a modified semicircle ground plane and a semicircle modified radiation patch. The bandwidth of the proposed antenna could increase by properly adjusting the dimensions of the ground plane and the radiation patch. The measured results show that the proposed monopole antenna offers a bandwidth from 2.95 to 11...
An accurate and efficient equivalent beam model(EBM) for a planar compliant mechanism with ellipticalflexure hinges is presented. First, based on 3D finite element analysis (FEA) for one-eighth of a single elliptical flexure hinge, a set of fictitious beams with identical stress and stiffness characteristics is derived. Then the static and dynamic performances of an eight-bar compliant mechanism with...
This paper presents a new proof-of-concept design of inchworm-type piezoelectric actuator for precision positioner which avoids the tight tolerance and could be easily assembled. The proposed design uses two parallel linear guiding rods as a guide different from the previous configurations which adopted a guide channel or a moving shaft and the clamping clearance is adjustable. For the optimum design...
This paper presents the comparison of two different rotational stiffness equations of single-notch circular flexure hinge with FEA results. The errors of these equations increase with t/r ratios (r is the radius and t is the thickness of the hinge). In order to develop accuracy rotational stiffness equation for 0.04lest/rles0.8, a simple empirical equation is formulated based on FEA results with errors...
In the paper, a dynamic model that has two inputs (voltage and load) is presented. Nonlinearities in piezoceramics when they are subject to two inputs are classified into memory storage mechanisms and the memoryless mechanisms. A multi-layer neural network is presented in order to describe the memoryless mechanism, which represents the cross coupling effects between two inputs. A numerical form of...
This paper presents a novel proof-of-concept design of an inchworm-type piezoelectric actuator. The proposed design uses two parallel linear guiding rods with ball bearings as a guide different from the previous configurations which adopt a guide channel or a moving shaft. Finite element analysis has been used to achieve the optimal design parameters with the frame stiffness, the dynamic performance...
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