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Since the dawn of the Late Preclassic Period, the archetypical figure of the Old Man started to adorn a variety of artifacts manufactured by Maya artists and artisans. This article aims to present and examine an unprovenanced effigy-flute whose poly-globular resonator has been adorned with the visage of the toothless nonhuman being. Traditionally referred as God N, God D, or Itzamnaaj/Itzam Kokaaj, depending on the context and his sphere of control, this theopolymorphic figure has been the subject of numerous extensive investigations. The fact that his wrinkled face has also been applied to the body of prestige woodwind artifacts suggests a possible symbolic link between the divinity, the sonorous field, the instrumental practice, and ritual performances. However, the topic has received little scholarly attention. Dated from the Late Classic period and registered under inventory number 1981.033, this aerophone is currently part of the Musée des Instruments de Music's permanent collection (mim) held in Brussels, Belgium. Furthermore, this sounding artifact shall be considered as a unique example of sonorous mediation with the supersensible given the fact that it combines significant iconographic features with a specific organological configuration. Therefore, the analysis of the flute contributes to better comprehend the figure of the elderly Maker. [ABSTRACT FROM AUTHOR]

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The design and implementation of a microstrip antenna with an insertion in the feed line of a metamaterial structure, which from a hybrid perspective combines split ring resonators (SRR) and complementary split ring resonators (CSRR), for the band of 2.4 GHz is presented in this paper. The geometrical parameters of the structure are varied in order to evaluate the response of resonance frequency and the radiation pattern of the proposed antenna. The metamaterial structure adjacent to the power line produces a considerable increase in the bandwidth concerning to that of the conventional antenna, caused by the overlapping of the frequency bands produced by the radiant patch and the left-handed structure. The bandwidth of the antenna with metamaterial inclusion is increased to twice the expected in the original patch antenna, from 2.74% to values ranging from 4.55% to 6%, at expenses of gain degradation, but without significantly affecting the coupling, and maintaining a suitable directivity. Simulation and measured results are presented and show that the proposed metamaterial structure associated with the transmission line of microstrip antennas is a novel way of using SRR and CSRR, which allows suppressing the narrow bandwidth constraint. [ABSTRACT FROM AUTHOR]

In this paper is presented a study of the insertion of metamaterial structures in a rectangular patch antenna fed by microstrip line linear polarization to achieve increased bandwidth. The main characteristics of left-handed materials are analyzed and their behavior is investigated inside the antenna, which allows obtaining an increase bandwidth and improve some of the fundamental parameters in the design of rectangular patch antennas by applying the theory of themselves and simulation tools supported by computer-assisted. Initially a study of the influence that makes is performed, the cell structure composed by complementary ring resonators open square in shape with their respective "gaps" associated to the patch and position thereof on the parameters of interest microstrip antenna especially bandwidth. The results obtained allowed to conclusions that the location of metamaterial associated power line exerts a marked influence on the radiating structure; an increase in bandwidth and a decrease in efficiency over conventional microstrip antenna structures occur no left-handed. Besides confirm that the increased the dimensions of the complementary rings cause a decrease in the resonance frequency. Finally, the design of a microstrip antenna with left-handed structures for the 2.4 GHz ISM band is presented. [ABSTRACT FROM AUTHOR]

In this paper an improved technique is outlined to design filters in planar configurations. The new procedure is applied to enhance the performance of these devices. This work illustrates that complementary split-ring resonators (CSRRs), electrically coupled to a microstrip transmission line and split-ring resonators (SRRs) magnetically coupled to afinline structure can be applied to improve the design of such filters. For this purpose, classical variants of millimeter wave filters have been analyzed. These components include microstrip low-pass filters, finline bandpass/bandstop filters and antipodal finline bandstop filters. The properties of these configurations are discussed; the experimental data are in good agreement with the simulations. The results show the usefulness and validity of the new structures as it is possible to achieve a very low insertion loss and very sharp transition bands with high rejection capabilities. [ABSTRACT FROM AUTHOR]

Copyright of Superficies y Vacío is the property of Sociedad Mexicana de Ciencia y Tecnologia de Superficies y Materiales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A detailed study about the conditions to obtaining a multielement optical resonator is made with the help of the fractional Fourier transform, the self-consistent field theory, and the ray transfermation of an optical system. The article makes emphasis upon the ease of flat mirror multielement optical resonators, by finding an invariance for the width of girdle of the Light beam with regards to the fractional Fourier transform in the canonic mounting of the Longmann type I. [ABSTRACT FROM AUTHOR]

With the objective of study certain acoustic phenomena, such as resonance, absorption and reflection of the sound is presented the design and development of a practice. To achieve this goal, different materials are used and as main tool a Helmholtz Resonator. In the same way, it is specified what a Helmholtz Resonator is, the components of the utilized equipment, its assembly, the procedure to develop the practice; the same as the results and their correspond-ing analyses. Also the experience is supplemented applying a model of camera anecoica with the purpose of obtain-ing better conditions, under which the measurements are made. The study is based on the experimental work and it is implemented like an illustration form or explanation of the phenomena of absorption and reflection of the sound. [ABSTRACT FROM AUTHOR]