Showing papers by "George A. Kyriacou published in 1993"

A reconstruction algorithm of electrical impedance tomography with optimal configuration of the driven electrodes

Abstract: A reconstruction algorithm for electrical impedance tomography (EIT) is presented. The least-squares (LS) method is applied and a formulation similar to that of the perturbation method is found. The main difference from perturbation lies with the sensitivity matrix, which here is replaced by the Jacobian matrix, defined in terms of the partial derivatives of every sensing electrode pair voltage difference with respect to every element's conductivity. The mutual position between the active electrodes is chosen to give optimum sensitivity. The results shown that the algorithm presented here has a better convergence and needs fewer iterations than the perturbation method. >

The edge admittance model for the study of microstrips on uniaxial substrate

Abstract: The edge admittance model of a microstrip structure is applied for a semi infinite conductor over a grounded uniaxial substrate using the Wiener-Hopf technique. Explicit expressions for all the scattered field components, as well as for the surface wave modes characteristic equations, are given. The TEM wave reflection coefficient in a simple closed form expression is developed, utilizing a thin substrate approximation. The effects of the anisotropy ratio on this reflection coefficient and on the characteristics of a rectangular microstrip antenna are examined.