Applying B-Spline Biorthogonal Wavelet Basis Functions to the Method of Moments in Solving Poisson equation

The aim of this paper is to introduce the application of B-spline biorthogonal wavelet with various orders (number of vanishing moments) in Electrostatic problems and making improvement in the moment method development. Due to the order of wavelet, the impedance matrix resulting in this problem is sparsified by wavelet, and consequently, the solution can be obtained rapidly. To illustrate these concepts, the two-body problem of parallel square conducting plates is presented. To demonstrate the effectiveness and accuracy of the proposed technique, numerical results for charge density potential, capacity, and error relative for different order of B-spline biorthogonal wavelets and dielectric constant are presented. Results are compared to the previous work done and published, excellent results are obtained

Nueva estructura convertidor de modos ancha banda TM01-a-TE11

A novel mode converter that transforms circular waveguide transverse magnetic (TM01) to transverse electric (TE11) circular waveguide is investigated, providing over 48% bandwidth of extraneous-mode-free operation at a conversion loss of less than 0.05dB. The design philosophy is based upon the unique use of two intermediate modes: coaxial TEM and a rectangular waveguide TE10, which provide input to output isolation of converter modes

Miniaturized microstrip patch antenna with defected ground structure

The aim of this work is to miniaturize a microstrip patch antenna resonating at 3 GHz. For this purpose, defected ground structure (DGS) has been employed to shift the resonance frequency of an initial microstrip antenna from 5.7 GHz to 3 GHz by disturbing the antenna's current distribution. The proposed DGS is incorporated in the ground plane under the patch antenna to improve its performances. Finally, a miniaturization up to 50%, with respect to the conventional microstrip antenna, is successfully accomplished. A prototype of the antenna was fabricated with the FR4 substrate and tested. The measurements results were in good agreement with simulation results

Duplexor banda ancha en tecnología de guía de onda para aplicaciones satélite

A wideband diplexer is designed and constructed to demonstrate the feasibility of using stepped waveguide junctions for diplexer designs. It consists of two channel filters and a Tee E-plane junction. The relative bandwidth of the whole diplexer is about 64%. Two versions of this device has been constructed and tested in the C-band. The inputs and outputs return losses were less than -25dB, the isolation is > 80dB and the transmission loss was 0.1dB. Moreover, a manufacturing tolerance has been taken into account at the design step, and therefore, the designed diplexer need not be tuned after manufacture

Desfasadores diferenciales 90º y 180 banda completa (40%) en guía de onda para aplicaciones de radioastronomía

Two differential phase shifters are designed and tested to work in broadband applications exhibiting excellent features. A phase delay of 90º or 180º with respect to a waveguide with the same length is obtained by including several steps inside the waveguides. The relative bandwidth of both phase shifters is about 40%. Two versions of 90° and 180° have been designed in the Ku-band. The return losses were about 25dB and the phase were about ±2° and ±3° for 90° and 180° phase shifter respectively. Moreover, a manufacturing tolerance has been taken into account at the design, and therefore, the designed phase shifters need not be tuned after manufacture

Full-Band OMT turnstile en tecnología de guía de onda de altura reducida para aplicaciones satélite

An orthomode transducer with a circular waveguide input and two rectangular waveguide outputs is described. The design utilizes a reduced height turnstile and two identical reduced height E-plane power combiners. A Ku band version of this device has been constructed and tested. The inputs and outputs return losses were less than -30dB, the isolation between the two rectangular outputs is > 60dB and the transmission loss was 0.1dB. Moreover a yield analysis has been done for various tolerances assuring a precision of 0.05mm ± that indicate a high stability of the possible errors of the values of the designing variables

Influence de variation de la distance de séparation entre les antennes Patch

Ce travail présente l’influence de variation de la distance de séparation entre deux antennes patch rectangulaire

Characterization and modeling of Schottky diodes up to 110 GHz for use in both flip-chip and wire-bonded assembled environments

This paper presents a wideband model, from Direct Current (DC) to W band, for a single Anode Schottky Diode based on a commercial VDI chip. Different measurements have been performed to obtain a complete large-signal equivalent circuit model suitable for the device under consideration up to 110 GHz, and for its integration in planar circuits. The modeling has been done using a combination of DC, capacitance measurements, and RF scattering measurements. The test structure for on-wafer S-parameter characterization has been developed to obtain an equivalent circuit for Coplanar to Microstrip (CPW-Microstrip) transitions, then verified with 3D Electromagnetic (EM) tools and finally used to de-embed device measurements from empirical data results in W band. 3D EM simulation of the diodes was used to initialize the parasitic parameters. Those significant extrinsic elements were combined with the intrinsic elements. The results show that the proposed method is suitable to determine parameters of the diode model with an excellent fit with measurements. Using this model, the simulated performance for a number of diode structures has given accurate predictions up to 110 GHz. Some anomalous phenomena such as parasitic resistance dependence on frequency have been found.The authors would like to thank the Spanish Ministries of Science and Innovation (MICINN) and of Economy and Competitiveness (MINECO) for the financial support provided through projects CSD2008-00068, TEC2011-29264-C03-01 and FEDER co-funded TEC2011-29126-C03-01. The authors express their gratitude to the Spanish Agency AECI though its program ‘Becas para Extranjeros No Iberoamericanos para Estudios de Postgrado, Doctorado y Postdoctorado en Universidades y Centros Superiores en España’

Sistema de alimentación de antenas con dual polarización circular

A dual circular polarization feed antenna system for satellite communication is described. It consists of a septum OMT-Polarizer type, and two identical duplexers formed by a plane T-junction and of two iris filters, along with two electric field rotators since the vectors of the electric field in the rectangular ports must be vertical. This 4-port system transmits and receives radio frequency signals in double track in which the transmission Tx is made through two ports having as a access the standard rectangular waveguide WR42 and the reception RX is made also through two ports having as a access the standard rectangular waveguide WR28. To separate the two ways with the circular common port (or rather on the level of the antenna), as well in the transmission as in the reception, we used double circular polarization: right hand circular polarization (RHCP) and left hand circular polarization (LHCP)

Polarización circular ultra-ancha banda para aplicaciones satélite

The design and fabrication of an Ultra broadband OMT-polarizer is discussed here. The principal advantages of this topology relay on both the instantaneous bandwidth and the axial ratio improvement. Experimental measurements exhibit very good agreement with the predicted results given by Mician μwave wizard. The structure provides an extremely flat axial ratio (AR25dB at all ports over the extended Ku band (60%). Moreover, yield analysis and scaling properties demonstrate the robustness of this design against fabrication tolerances