THE INADEQUATE EMPLOYMENT OF ULTRA-HIGH-PERFORMANCE FILTERS IN ELECTRONICS INDUSTRY
CHAPTER ONE
- INTRODUCTION
- BACKGROUND OF THE STUDY.
A superconductor is an element, inter-metallic alloy, or compound that conduct electricity without resistance below a certain temperature. The resistance is undesirable because it produces losses in the energy flowing through the material .The unique properties of super conductors have led to the development of tiny measuring and computing device that are superior in performance of their non-super conducting counterparts.
Prediction of many properties of superconductors which are in good agreement with experimental information are made by superconductivity which describes how and why the electrons in a conductors may form an ordered super conducting state. initially, the number of known super-conductors was quite small, this was so in part because experiments were then confined to temperature above 1k(-450of), the minimum temperature readily available using liquid helium (4He) as a refrigerant, so that only superconductors with transition temperatures above 1k could be discovered.
Despite the existence of a successful microscopic theory of super conductivity, there are no completely reliable rules for predicting whether a metal will be a superconductor. Certain trends and co-relations are apparent among the known superconductors, however some with obvious basis in the theory and these provide empirical guidelines in the search for new superconductors. Superconductor with relatively highly transition temperature tend to be rather poor conductors in the normal state. Ordinarily, a large electrical conductivity is accompanied by a large thermal conductivity as in case of copper, used in a electrical wiring and cooking pans.
However, the thermal conductivity of a pure superconductor is less in
the superconducting state than in a normal state, and at very low temperature approaches zero. The appearance of the superconducting state is accompanied by quite drastic changes in both the thermodynamic equilibrium and thermal transport properties of a superconductor at high frequencies which differ from the zero frequency behavior. It is found that, super conductors do not have zero resistance to the flow of current in the radio frequency (up to about 10⁸ Hz) and microwave-frequency (from 10⁸ to about 10¹¹ Hz) region of the electromagnetic spectrum. The resistance and the accompanying electrical energy loss are still much smaller than
in the normal state, but they are not zero, and the increase with the increasing frequency.
