Jordi Romeu Robert

Electromagnetic modeling and characterization of steel fiber reinforced concrete during the pouring process

A sensor based on a coplanar waveguide structure was designed to perform non-destructive tests for material characterization in which the measurement can be done only on one side of the sample. The measurements were compared with the impedance of a capacitor filled with the same material. The permittivity and insertion loss of the sensor showed valuable information about the setting process of a mortar slab during the first 28 days of the hardening process, and a good correlation between both measurements was obtained, so the proposed setup can be useful for structural surveillance and moisture detection in civil structures.In this paper, a complex electromagnetical model for the SFRC is derived, and a mathematical model for the obtention of the effective relative permittivity is described. A static analysis setup is presented and results of a two weeks duration analysis are analyzed. Finally, nsome preliminary conclusions for the time-dependence behaviour of SFRC are formulated.A sensor based on a coplanar waveguide structure was designed to perform non-destructive tests for material characterization in which the measurement can be done only on one side of the sample. The measurements were compared with the impedance of a capacitor filled with the same material. The permittivity and insertion loss of the sensor showed valuable ninformation about the setting process of a mortar slab during the first 28 days of the nhardening process, and a good correlation between both measurements was obtained, so the proposed setup can be useful for structural surveillance and moisture detection in civil structures.

Effect of random errors in cylindrical

Expressions have been derived previously to predict the effect of random errors in planar near-field measurements. Similar equations for cylindrical near-field measurements are not available. Random errors are due to A/D (analog-to-digital) quantization, receiver noise or random room scattering; their nature is additive and will limit the accuracy of the far-field pattern. Since the near-to-far-field transformation is a linear operator the effect of additive noise can be analyzed by superposition. The near-field noise is assumed to be complex Gaussian noise, space stationary, with zero mean, and variance sigma /sup 2/. In the present analysis, the statistical characteristics of the far-field noise are found. Numerical simulations have been carried out to validate the expressions obtained.<<ETX>>Expressions have been derived previously to predict the effect of random errors in planar near-field measurements. Similar equations for cylindrical near-field measurements are not available. Random errors are due to A/D (analog-to-digital) quantization, receiver noise or random room scattering; their nature is additive and will limit the accuracy of the far-field pattern. Since the near-to-far-field transformation is a linear operator the effect of additive noise can be analyzed by superposition. The near-field noise is assumed to be complex Gaussian noise, space stationary, with zero mean, and variance sigma /sup 2/. In the present analysis, the statistical characteristics of the far-field noise are found. Numerical simulations have been carried out to validate the expressions obtained.A closed expression for the autocorrelation of the far field noise due to random near field noise in a cylindrical near to far field transformation is derived. This expression is employed to obtain bounds for the computed radiation pattern for a given near field signal to noise ratio.

Effect of random errors in antenna cylindrical near-field measurements

Expressions have been derived previously to predict the effect of random errors in planar near-field measurements. Similar equations for cylindrical near-field measurements are not available. Random errors are due to A/D (analog-to-digital) quantization, receiver noise or random room scattering; their nature is additive and will limit the accuracy of the far-field pattern. Since the near-to-far-field transformation is a linear operator the effect of additive noise can be analyzed by superposition. The near-field noise is assumed to be complex Gaussian noise, space stationary, with zero mean, and variance sigma /sup 2/. In the present analysis, the statistical characteristics of the far-field noise are found. Numerical simulations have been carried out to validate the expressions obtained.<<ETX>>Expressions have been derived previously to predict the effect of random errors in planar near-field measurements. Similar equations for cylindrical near-field measurements are not available. Random errors are due to A/D (analog-to-digital) quantization, receiver noise or random room scattering; their nature is additive and will limit the accuracy of the far-field pattern. Since the near-to-far-field transformation is a linear operator the effect of additive noise can be analyzed by superposition. The near-field noise is assumed to be complex Gaussian noise, space stationary, with zero mean, and variance sigma /sup 2/. In the present analysis, the statistical characteristics of the far-field noise are found. Numerical simulations have been carried out to validate the expressions obtained.A closed expression for the autocorrelation of the far field noise due to random near field noise in a cylindrical near to far field transformation is derived. This expression is employed to obtain bounds for the computed radiation pattern for a given near field signal to noise ratio.