A planar magneto-inductive lens for three-dimensional subwavelength imaging

A planar near-field magnetoinductive lens operating in the microwave range is presented. The proposed device consists of two parallel planar arrays of metallic broadside coupled (BC-) split ring resonators (SRRs), or BC-SRRs. Power coming from a point-like source located in front of the lens is focused into a receiver located in free space behind the device. This focus is clearly removed from the back side of the lens, and has a size which is an order of magnitude smaller than the free space wavelength of the incoming radiation. The imaging properties of the device mainly relies on the excitation of magnetoinductive surface waves on the BC-SRR arrays. By simply scaling the BC-SRRs size, as well as the arrays periodicity, the frequency of operation of the device can be tuned over a wide frequency range. Thus the proposed design is potentially useful for many applications ranging from megahertzs to terahertzs.Comment: 14 pages, 3 figures, submitted to Applied Physics Letter

Experimental demonstration of a mu=-1 metamaterial lens for magnetic resonance imaging

In this work a mu=-1 metamaterial (MM) lens for magnetic resonance imaging (MRI) is demonstrated. MRI uses surface coils to detect the radiofrequency(RF) energy absorbed and emitted by the nuclear spins in the imaged object. The proposed MM lens manipulates the RF field detected by these surface coils, so that the coil sensitivity and spatial localization is substantially improved. Beyond this specific application, we feel that the reported results are the experimental confirmation of a new concept for the manipulation of RF field in MRI, which paves the way to many other interesting applications.Comment: 9 pages, 3 figure

CTE SE-F: Addendum to two articles on masonry structures.

El artículo revisa las diferencias más significativas que existen entre el Eurocódigo 6 - Estructuras de Fábrica, UNE-ENV 1996-1-1 de junio de 1995, y la versión final (noviembre de 2003) del Código Técnico de la Edificación español en el campo de las estructuras de fábrica en sentido lato, haciendo hincapié en los cambios introducidos en el método de cálculo por asimilación a pórticos y en el método simplificado. Las diferencias existentes han llevado a comparar numéricamente los métodos propuestos con otros estudiados en trabajos anteriormente realizados, comparación que se refleja en una serie de gráficos.[Abstract]The article reviews the most significant differences between Eurocode 6 - Design of masonry structures, EN 1996-1-1 June 1995, and the final version (November 2003) of the spanish Building Technical Code in the field of masonry structures broadly, emphasizing the changes in the method calculation by assimilation porches and in the simplified method. The differences have led to numerically compare with other proposed methods studied in previous work, compared reflected in a series of graphs

Use of Mutual Coupling to Decrease Parasitic Inductance of Shunt Capacitor Filters

In this paper, we propose and study several new designs of a shunt capacitor filter with two surface-mount technology capacitors. These designs make use of mutual inductance effects to increase the attenuation provided by the filter in the range of high frequencies where the filter behaves inductively. We provide lumped element circuitmodels for the proposed designs that allow identification of the key inductive parameters that determine the high-frequency performance of these filters. We obtain the equa- tions relating these parameters to the effective inductance of the filter, which can be used to compare the high-frequency behavior of different filter designs. We have fabricated and measured several compact shunt capacitor filters with improved performance at high frequencies. We have found that, compared with a shunt capacitor filter with one capacitor, a proper filter design with two capacitors can easily increase in 15–20 dB the high-frequency attenuation provided by the filter. This design also outperforms by 10–15 dB a traditional shunt capacitor filter with two capacitors closely placed. Moreover, this improvement is obtained with no increase in size, cost, or time of design of the filter.Ministerio de Economía Y Competitividad TEC2014-54097-