Colaboracin en las tareas de Investigacin del Laboratorio de Radiofrecuencia, Microondas y MilimtricasDescripcin del proyecto:Colaboracin en el diseo, fabricacin y medida de circuitos activos (amplificadores, antenas activas,...) y pasivos (antenas, filtros, acopladores,...) de alta frecuencia. El objetivo de la colaboracin es que el estudiante adquiera conocimientos de diseo de circuitos, se familiarice con el uso de simuladores tanto circuitales como electromagnticos, aprenda tcnicas bsicas de medida as como el manejo de la correspondiente instrumentacin, y adquiera experiencia en la fabricacin de circuitos de microondas, mediante su incorporacin a las tareas de investigacin que se desarrollan en el laboratorio.

PUNTO 1: DISEO, FABRICACION Y MEDIDA DE CIRCUITOS ACTIVOS Y PASIVOSCircuitos Activos y Pasivos de Microondas:Los circuitos de microondas estn divididos en dos grandes grupos: circuitos activos y circuitos pasivos. Los circuitos pasivos no agregan potencia a la seal que reciben, mientras que los activos s que pueden agregarla. Los circuitos pasivos incluyen desde elementos discretos como resistencias, inductancias y capacitancias hasta circuitos ms complejos, tales como: Filtros, divisores, combinadores, duplexores, circuladores, atenuadores, lneas de transmisin... Entre los circuitos que pueden ser tanto activos como pasivos, estn las antenas, multiplexores, mezcladores... Dentro de los circuitos activos se encuentran los RFICs, diodos, MMICs, receptores, moduladores, osciladores...PUNTO 2: SIMULADORES CIRCUITALES Y ELECTROMAGNETICOSComputer-aided design (CAD) software packages have become essential tools for the analysis, design, and optimization of RF and microwave circuits and systems. Several microwave CAD products are commercially available, including Microwave Office (Applied Wave Research), ADS (Agilent Technologies), Microwave Studio (CST), Designer (Ansoft), and many others. RF and microwave CAD packages can be divided into two types: those that use physics-based solutions, where Maxwells equations are numerically solved for physical geometries such as printed circuit geometries or waveguides, and circuit-based solutions, which use equivalent circuits for various elements, including distributed elements, discontinuities, coupled lines, and active devices. Some packages combine these two approaches. Both linear and nonlinear mod- eling, as well as circuit optimization, are generally possible. Although such computer programs can be fast, powerful, and accurate, they cannot serve as a substitute for engineering experience and a good understanding of microwave principles.

A typical design process usually begins with specifications or design goals for the circuit or system. Based on previous designs and his or her experience, an engineer can develop an initial design, including specific components and a circuit layout. CAD can then be used to model and analyze the design, using data for each of the components and including effects such as loss and discontinuities. The software can be used to optimize the design by adjusting some of the circuit parameters to achieve the best performance. If the specifications are not met, the design may have to be revised. CAD tools can also be used to study the effects of component tolerances and errors to improve circuit reliability and robustness. When the design meets the specifications, an engineering prototype can be built and tested. If the measured results satisfy the specifications, the design process is completed. Otherwise the design will need to be revised and the procedure repeated.

Without CAD tools the design process would require the construction and measurement of laboratory prototypes at each iteration, which is expensive and time consuming. Thus, CAD can greatly decrease the time and cost of a design while enhancing its quality. The simulation and optimization process is especially important for monolithic microwave integrated circuits because these circuits cannot easily be tuned or trimmed after fabrication.

CAD techniques are not without limitations, however. Of primary importance is the fact that any computer model is only an approximation to a real-world physical circuit and cannot completely account for the inevitable differences due to component and fabrication tolerances, surface roughness, spurious coupling, higher order modes, junction discontinuities, thermal effects, and a number of other practical issues that can occur with a physical circuit or device. PUNTO 3: FABRICACION DE CIRCUITOS DE MICROONDAS

PUNTO 4: INSTRUMENTACION ESPECIFICA DE MEDIDA DE RADIOFRECUENCIA Y MICROONDAS