Resonance of Superconducting Microstrip Antenna with Aperture in the Ground Plane

This paper presents a rigorous full-wave analysis of a high Tc superconducting rectangular microstrip antenna with a rectangular aperture in the ground plane. To include the effect of the superconductivity of the microstrip patch in the full-wave analysis, a complex surface impedance is considered. The proposed approach is validated by comparing the computed results with previously published data. Results showing the effect of the aperture on the resonance of the superconducting microstrip antenna are given

Performance evaluation of a natural and synthetic compound as corrosion inhibitors of API 5L X52 steel in hydrochloric acid media

A comparative study of corrosion protection of pipeline steel API 5L X52 in hydrochloric acid solution was conducted between a “synthetic commercial corrosion inhibitor” and a “green corrosion inhibitor” extract from the leaves of Ruta Chalepensis (LERC). It has been found that LERC inhibiting ability is quite high and depends strongly on its concentration in the corrosive solution. At an elevated temperature (353K), the LERC inhibitor demonstrates higher effectiveness than the commercial inhibitor. The electrochemical study showed that the LERC inhibitor affects both the anodic and cathodic corrosion reactions. The LERC adsorption mechanism on steel surface was assessed and some thermodynamic parameters of its process were determined

Evolution of microstructure and crystallographic texture during dissimilar friction stir welding of duplex stainless steel to low carbon-manganese structural steel

Electron backscattered diffraction (EBSD) was used to analyze the evolution of microstructure and crystallographic texture during friction stir welding of dissimilar type 2205 duplex stainless steel (DSS) to type S275 low carbon-manganese structural steel. The results of microstructural analyses show that the temperature in the center of stirred zone reached temperatures between Ac 1 and Ac 3 during welding, resulting in a minor ferrite-to-austenite phase transformation in the S275 steel, and no changes in the fractions of ferrite and austenite in the DSS. Temperatures in the thermomechanically affected and shoulder-affected zones of both materials, in particular toward the root of the weld, did not exceed the Ac 1 of S275 steel. The shear generated by the friction between the material and the rotating probe occurred in austenitic/ferritic phase field of the S275 and DSS. In the former, the transformed austenite regions of the microstructure were transformed to acicular ferrite, on cooling, while the dual-phase austenitic/ferritic structure of the latter was retained. Studying the development of crystallographic textures with regard to shear flow lines generated by the probe tool showed the dominance of simple shear components across the whole weld in both materials. The ferrite texture in S275 steel was dominated by D 1, D 2, E, E¯ , and F, where the fraction of acicular ferrite formed on cooling showed a negligible deviation from the texture for the ideal shear texture components of bcc metals. The ferrite texture in DSS was dominated by D 1, D 2, I, I¯ , and F, and that of austenite was dominated by the A, A¯ , B, and B¯ of the ideal shear texture components for bcc and fcc metals, respectively. While D 1, D 2, and F components of the ideal shear texture are common between the ferrite in S275 steel and that of dual-phase DSS, the preferential partitioning of strain into the ferrite phase of DSS led to the development of I and I¯ components in DSS, as opposed to E and E¯ in the S275 steel. The formations of fine and ultrafine equiaxed grains were observed in different regions of both materials that are believed to be due to strain-induced continuous dynamic recrystallization (CDRX) in ferrite of both DSS and S275 steel, and discontinuous dynamic recrystallization (DDRX) in austenite phase of DSS

Optimization of superconducting antenna arrays using RBF neural network

In this work, RBF neural network is used to optimize the radiation pattern of non-uniform linear arrays of High superconducting rectangular microstrip antennas, on uniaxial anisotropic substrate. Using superconductors can reduce the insertion loss, and obtain a rather high gain. The full-wave method is used to computing the resonant frequency, and radiation pattern of superconducting rectangular antennas. Galerkin method is used to obtain feasible solutions, for the array by matching the desired Di and actual array patterns Fi. The results obtained from the simulation show that we reached our goals by a great degree of validity

Rigorous Analysis of a Compact Triangular Antenna Array Using the Spectral Domain Method

Abstract The main objective of this work is the characterization of triangular array antenna with circular form by using the spectral domain technique. Firstly, the spectral domain formulation of single triangular patch antenna is given, in order to calculate its resonant frequencies and its radiation patterns. Then, we calculate and plot the total radiated field which is the multiplication of a single element radiation by the array factor, when patches are made in a circular arrangement. Comparing to the exiting array antenna design, the numerical results, obtained from the implementation of our calculations, have shown that the networking increases the gain, improves the directivity and controls the bandwidth with a compact form of the antenna arrangement. In addition the effects of different parameters of the structure on its performances are presented

Resonance of High Tc Superconducting Microstrip Patch in a Substrate-Superstrate Configuration

The effect of a protecting dielectric superstrate on the resonance of a high Tc superconducting microstrip patch is investigated. The analysis approach is based on the spectral-domain method of moments in conjunction with the complex resistive boundary condition. The complex surface impedance of the superconducting thin film is determined using London’s equation and the two-fluid model of Gorter and Casimir. Numerical results show that the resonant frequency of the high Tc superconducting rectangular patch decreases monotonically with increasing superstrate thickness, the decrease being greater for high permittivity loading