Métodos eficientes para sintetizar filtros de microondas con perfil suave

El objetivo de este trabajo es mejorar dos métodos de síntesis. Ambos métodos calculan el coeficiente de acoplo de un filtro de microondas, a partir de las especificaciones y por medio de la Teoría de Acoplo de Modos. En este trabajo se usan algunas teorías clásicas y nuevos algoritmos para reducir errores númericos y disminuir el coste computacional de los métodos. Para verificar los objetivos se presentan varios diseños.The aim of this work is to improve two synthesis methods. Both methods obtain the coupling coefficient of a microwave filter, starting with the specifications and by means of solving the Coupled-Mode Theory equations. Classical theories are applied in the methods in order to improve them in terms of computational cost and numerical errors. Several routines and algortihms are presented among this work. In addition, in order to check the objectives, there are several novel designs in each section.Menargues Gómez, E. (2013). Métodos eficientes para sintetizar filtros de microondas con perfil suave. http://hdl.handle.net/10251/33396

All-metal 3-D Frequency Selective Surface with Versatile Dual-Band Polarization Conversion

International audienceA dual-band periodic structure is here proposed, which allows for versatile frequency selectivity and polarization conversion functionality. The structure is a monolithic full-metal piece, and it is built from the arrangement of unit-cells consisting of waveguide sections at cutoff loaded with compound perforations. The topology of such unit-cells enables the efficient and independent interaction with vertical and horizontal electric field components illuminating the periodic structure. A circuit model is proposed to characterize the cells and understand their behaviour. Three different examples of cells are designed to illustrate the structure versatile functionality. One of these examples is manufactured, consisting of a dual-band structure that converts linear polarization into circular with orthogonal senses of rotation at each band. The experimental results are in good agreement with the theoretical predictions, thus validating the underlying operation mechanism and its practical feasibility

Progress on metal Additive Manufactured waveguide filters: from L-band to Q/V-band

International audienceThis conference papers presents recent innovations in the domain of waveguide filters fabricated using metal Additive Manufacturing. In particular, two types of filters for space applications are presented: a L-band reconfigurable filter that uses a new type of combline cavity and that achieves x5 mass reduction with respect to classic combline filters at these frequencies; and QV-band output filters with different level of rejection. The article also discusses key design guidelines for the design of such filters

Design Approaches for Additive Manufacturing of Waveguide Filters

International audienceThis conference papers discusses several design approaches to successfully design and fabricate waveguide filters using Additive Manufacturing. The article covers lowpass and bandpass filters in different topologies and compatible with different printing directions. All examples are backed with fabrication examples

Solving Sub-Wavelength Lattice Reduction in Full-Metal Front-Ends for Dual-Polarized Active Antennas

International audienceThis article proposes an original structure of evanescent quadridge antenna (EQA) to conceive dual-polarized full-metal front-ends that can be used in active antennas (AAs) with wide field-of-view (FoV). An original design methodology is here proposed that allows to induce radiation from subwavelength squared apertures based on the use of evanescent and quadridge waveguides. The proposal is illustrated by means of a design with 4.5% bandwidth providing dual-circular polarization (CP) with good performance up to 50 degrees-scanning even in the diagonal plane. For comparison purposes, a metallic benchmark is also proposed, which is based on the use of classical quadridge horns. Such comparative analysis allows to understand the superior performance of the proposed concept and its main advantage: it allows to avoid the excitation of the first high order mode in the squared quadridge aperture. The excitation of such spurious mode in the antenna is explained in terms of simple equivalent circuit models characterizing the aperture periodic discontinuity

Cost-effective dual-polarised leaky-wave antennas enabled by three-dimensional printing

International audienceThis study proposes a compact dual-polarised directive radiator whose complex prototyping is enabled by additive manufacturing. In addition to monolithic implementation, stereolitography followed by metal coating, it also provides high radio-frequency performance, low cost and low weight. Dual-channel simultaneous operation is supported thanks to the integration of an orthomode transducer within the structure. Entirely waveguide based, this compound radiating structure is specially well suited to be 3D-printed, and in principle, it allows scaling to match a specific frequency of operation. Both the antenna concept and the employed advanced manufacturing technique are validated experimentally through the realisation and measurement of two prototypes operating, respectively, at 30 and 60 GHz. The proposed architecture is easily amenable to be grouped in a compact higher-gain array, thus holding strong potential for platform-constrained applications, such as inter-satellite links between CubeSats

Synthesis of Versatile Functionalities in Arrangements of 3D Unit-Cells

International audienceThis contribution concentrates on the conception of periodic structures that are built from metallic three-dimensional unit-cells. Such arrangements allow synthesizing diverse functionalities such as polarization conversion, frequency filtering, and impedance matching. In addition, the topologies considered here can be built monolithically employing only metal, therefore providing multiple advantages, such as low insertion losses, high power handling and manufacturing certainty

The role of Additive Manufacturing in Space-borne Active Antenna

International audienceThis article aims at illustrating the role that Additive Manufacturing can play in the development of active antennas for space applications. Three relevant examples are considered: a new radiating element for low power consumption in LEO satellites, an iso-phase waveguide cluster to simplify the accommodation of active arrays in GEO payloads and antenna clusters to reduce the mass and cost of GEO DRAs

Vertically Printable Evanescent Mode Filters

International audienceThis work presents a new topology of evanescent mode filter (EMF) that allows for its efficient additive manufacturing (AM). Chamfered ridges which avoid the appearance of undesired supports when printed vertically (i.e., along the propagation axis of the filter) are considered. This strategy ensures accurate tolerances, reduced cost and it also enables monolithic manufacturing of the EMF as part of a feed chain. A circuit model is developed to explain the behavior of the new ridges as well as to speed up the overall filter design. The proposed concept and methodology are validated experimentally through the manufacturing and measurement of a prototype