Development of a high-performance W-band duplexer for plasma diagnosis using a single band with dual circular polarization

Discrepancia entre la información que aparece en el artículo que indica que el copyright es de Elsevier, y la información que aparece en la página de la revista y en el Copyright Clearance Center que indican © 2019 The Authors. Published by Elsevier B.V., así como que el artículo está publicado en Open Access under a Creative Commons licenceThis work presents the design and experimental validation of a high performance, compact, waveguide duplexer operating from 91.5 to 96.5 GHz for its integration in diverse W-band microwave equipment as in plasma diagnosis applications. It uses a single frequency band, with two signals discriminated by different orthogonal circular polarization, which is generated by means of a septum orthomode transducer (OMT) polarizer. Moreover, this component is optimized loaded with the horn antenna for improving the overall system performance. It is explained how these two components are integrated into a very compact duplexer, designed using efficient numerical algorithms. The manufacturing process by mean of high precision milling, and including electrical discharge machining (EDM) has led to excellent performances. The measured return loss level and isolation are higher than 30 dB, and the insertion loss level is below 0.3 dB. Finally, the key parameter in this device, which reflects the symmetry in the manufacturing process, i.e., the axial ratio, is lower than 0.6 dB for both polarizations, an excellent result showing the potential of the presented designThis work was supported by the Spanish government under grants (ADDMATE) TEC2016-76070-C3-1/2-R (Agencia Estatal de Investigación, Spain, Fondo Europeo de Desarrollo Regional: AEI/FEDER/UE) and the program of Comunidad de Madrid, Spain S2013/ICE-3000 (SPADERADARCM

Rigorous analysis of the parallel plate waveguide: From the transverse electromagnetic mode to the surface plasmon polariton

This is the accepted version of the following article: K. S. Reichel, N. Sakoda, R. Mendis, D. M. Mittleman, Evanescent wave coupling in terahertz waveguide arrays, Optics Express, 2013, 21, 14, 17249, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1029/2011RS004838/fullThis paper presents an analysis of the parallel plate waveguide, based on a hybrid mode formulation. The nonideal metallic conductors of the waveguide are treated as a media characterized by an equivalent permittivity. The frequencies of interest in the presented analysis are at the terahertz band (from 300 GHz to 30 THz), and appropriate models are used for the correct characterization of metallic conductors at these frequencies. The behavior of the electromagnetic field of the fundamental mode is studied in a wide frequency range. At low frequencies (microwave regime) the fundamental mode is the well-known transverse electromagnetic (TEM) mode; as frequency increases, the electromagnetic field changes significantly and a surface wave or surface plasmon polariton (SPP) behavior is observed at the highest frequencies of the terahertz band. This paper shows a unified formulation that explains this transformation in the electromagnetic field behavior.This work has been partially supported by the Spanish government program TEC2010–17795, the CONSOLIDER CSD2008–00068, and a PhD grant from Universidad Politécnica de Madrid

La política pública para la vivienda social ubicada en la periferia de la ciudad de Monterrey, Nuevo León, México

El crecimiento demográfico en las ciudades más grandes del norte de México aunado a los procesos de industrialización en el mercado internacional han marcado la pauta en su desordenado crecimiento urbano, con desarrollos habitacionales compuestos por hogares que buscan la oportunidad laboral situándose hacia las periferias de dichas ciudades sin contar con el equipamiento urbano mínimo para cumplir las necesidades del entorno para sus habitantes. En el presente artículo se exponen algunos de los factores causantes de dicho fenómeno y se analizan los aspectos del marco legal que se aplican en los conjuntos habitacionales ubicados hacia la periferia de la ciudad de Monterrey, México, así como los programas estatales y municipales que proponen el marco del desarrollo social para dichos desarrollos

Low-cost manufacturing by fused filament fabrication of microwave waveguide passive devices for space applications

Presentación en poster de impresión 3D de guias de onda

Novel dual-band single circular polarization antenna feeding network for satellite communications

In this paper a novel dual-band single circular polarization antenna feeding network for satellite communications is presented. The novel antenna feed chain1 is composed of two elements or subsystems, namely a diplexer and a bi-phase polarizer. In comparison with the classic topology based on an orthomode transducer and a dual-band polarizer, the proposed feed chain presents several advantages, such as compactness, modular design of the different components, broadband operation and versatility in the subsystems interconnection. The design procedure of this new antenna feed configuration is explained. Different examples of antenna feeding networks at 20/30 GHz are presented. It is pointed out the excellent results obtained in terms of isolation and axial ratio

Biorremediación con vermicomposta en la contaminación del suelo producida por hidrocarburos

Para hacer frente a la contaminación ocasionada por el petróleo, es necesario tener un conocimiento integral en los procesos de degradación de los hidrocarburos, para dar la solución más apropiada a los problemas producidos en los suelos. Entre las opciones más adecuadas y sustentables está la biorremediación, esta se ayuda de agentes biológicos para la degradación de compuestos peligrosos y/o poder reducir en un máximo su nivel de peligrosidad. En esta investigación se estudió y analizó el tratamiento y degradación de la turbosina aplicando biorremediación con ayuda de la lombriz roja californiana (Eisenia foetida) para lograr la restauración de las propiedades físico-químicas alteradas por consecuencia de dicho combustible. Se logró alcanzar un porcentaje aceptable dentro de la descontaminación (69% en máxima humedad y 66% en humedad mínima), reforzando esto con germinación de plantas las cuales lograron crecer de forma exitosa presentando características físicas notablemente más desarrolladas.To deal with the pollution caused by oil, it is necessary to have a comprehensive knowledge of the degradation processes of hydrocarbons, to give the most appropriate solution to the problems produced in soils. Among the most appropriate and sustainable options is bioremediation, this is helped by biological agents for the degradation of dangerous compounds and/or to reduce their level of danger as much as possible. In this research, the treatment and degradation of jet fuel was studied and analyzed by applying bioremediation with the help of the Californian red worm (Eisenia foetida) to achieve the restoration of the altered physicochemical properties as a consequence of said fuel. It was possible to reach an acceptable percentage within the decontamination (69% in maximum humidity and 66% in minimum humidity), reinforcing this with germination of plants which managed to grow successfully presenting noticeably more developed physical characteristics

Compact duplexing for a 680-GHz radar using a waveguide orthomode transducer

A compact 680-GHz waveguide orthomode transducer (OMT) and circular horn combination has been designed, tested, and characterized in a radar transceiver's duplexer. The duplexing capability is implemented by a hybrid waveguide quasi optical solution, combining a linear polarization OMT and an external grating polarizer. Isolation between the OMT's orthogonal ports' flanges was measured with a vector network analyzer to exceed 33 dB over a >10% bandwidth between 630 and 710 GHz. Calibrated Y-factor measurements using a mixer attached to the OMT ports reveal losses through the transmit and receive paths that sum to an average of 4.7 dB of two-way loss over 660-690 GHz. This is consistent with radar sensitivity measurements comparing the new OMT/horn with a quasi-optical wire grid beam splitter. Moreover, the radar performance assessment validates the OMT as a suitable compact substitute of the wire grid for the JPL's short-range 680-GHz imaging radar

Generation of organotypic multicellular spheres by magnetic levitation : model for the study of human hematopoietic stem cells microenvironment

Q4Q3Background and Objective: The characteristics of human hematopoietic stem cells are conditioned by the microenvironment of the bone marrow, where they interact with other cell populations, such as mesenchymal stem cells and endothelial cells; however, the study of this microenvironment is complex. The objective of this work was to develop a 3D culture system by magnetic levitation that imitates the microenvironment of human HSC. Methods and Results: Human bone marrow-mesenchymal stem cells, umbilical cord blood-hematopoietic stem cells and a non-tumoral endothelial cell line (CC2811, LonzaⓇ) were used to develop organotypic multicellular spheres by the magnetic levitation method. We obtained viable structures with an average sphericity index greater than 0.6, an average volume of 0.5 mm3 and a percentage of aggregation greater than 70%. Histological studies of the organotypic multicellular spheres used hematoxylin and eosin stains, and an evaluation of vimentin expression by means of immunohistochemistry demonstrated an organized internal structure without picnotic cells and a high expression of vimentin. The functional capacity of human hematopoietic stem cells after organotypic multicellular spheres culture was evaluated by multipotency tests, and it was demonstrated that 3D structures without exogenous Flt3L are autonomous in the maintenance of multipotency of human hematopoietic stem cells. Conclusions: We developed organotypic multicellular spheres from normal human cells that mimic the microenvironment of the human hematopoietic stem cells. These structures are the prototype for the development of complex organoids that allow the further study of the biology of normal human stem cells and their potential in regenerative medicine.https://orcid.org/0000-0002-9152-5552https://orcid.org/0000-0003-3075-9854https://orcid.org/0000-0002-0084-0339https://orcid.org/0000-0003-1881-9367N/