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International audience; Swarms of unmanned vehicles (air and ground) can increase the efficiency and effectiveness of military and law enforcement operations by enhancing situational awareness and allow the persistent monitoring of multiple hostile targets. The key focus in the development of the enabling technologies for swarm systems, is the minimisation of uncertainties in situational awareness information for surveillance operations supported by a 'system of systems' composed by static and mobile heterogeneous sensors. The identified critical enabling techniques and technologies for adaptive, informative and reconfigurable operations of unmanned swarm systems are: Robust Static sensor network design, mobile sensor tasking (including reallocation), Sensor fusion, Information fusion including behaviour monitoring. The work presented in this paper describes one of the first attempts to integrate all swarm related technologies into a practical demonstration, demonstrating the benefits of swarms of heterogeneous vehicles for defence applications used for the persistent monitoring of high value assets such as military installations and camps. The key enabling swarm system technologies are analysed and novel algorithms are developed and presented, which can be implemented in COTS based unmanned vehicles available today and have thus been designed and optimised to require small computational power, be flexible, reconfigurable and which can be implemented in a large range of commercially available unmanned vehicles (air and ground).

The present work has been conceived with two main objectives in mind. The first one being to summarize part of the research and development activities carried out at the Department of Communication Engineering at the University of Cantabria in the field of GaAs Monolithic Microwave Wave Integrated Circuits (MMICs) design and implementation. This thesis presents in fact many newly developed MMICs covering the implementation of diverse functions and applications. All the circuits are described in detail together with the associated design flow, with emphasis both on its theoretical justification and its practical application. The second objective is to serve as a guide and a supporting tool for future designs with the aim of facilitating the work of the MMIC designer, by presenting in detail the approach followed to ensure the correct functionality of the implemented circuits. Some new analysis methodologies will be also proposed with the potential to simplify and speed-up the design of complex circuits to ease and make more reliable the work of the microwave circuit designer in support of a first-time-right MMIC implementation. The Thesis covers both scientific and technological aspects with direct industrial application in the space sector. Part of the developed technologies and designs, assembly and characterization information have been in fact transferred to the space industry in order to manufacture and commercialize a new generation of S-Band Transponder currently in use in more than 10 space missions. RESUMEN: El presente trabajo de tesis se ha concebido con dos objetivos fundamentales. El primero, resumir buena parte de las actividades de investigación y desarrollo llevadas a cabo por el autor en el Departamento de Ingeniería de Comunicaciones (DICOM) de la Universidad de Cantabria en el campo del diseño de circuitos MMICs basados en AsGa. El segundo objetivo, no por ello menos relevante, es servir como guía y herramienta de apoyo para nuevos diseños, con la meta de facilitar el trabajo de futuros diseñadores de MMICs presentando en detalle el procedimiento seguido para asegurar el funcionamiento correcto de los circuitos implementados. Al mismo tiempo y a través de la experiencia ganada en el diseño de múltiples funciones circuitales empleando prácticamente todas las herramientas de simulación disponibles, se han propuesto nuevas metodologías de análisis con el potencial de simplificar y acelerar el diseño de circuitos MMICs complejos. Los circuitos y las correspondientes técnicas de diseño que serán objeto del presente trabajo tienen en común que se apoyan en la misma tecnología de fabricación (AsGa), se han desarrollado orientadas al campo de aplicación de las comunicaciones vía satélite (dando lugar, en algunos casos, a componentes calificados para espacio).El trabajo se focaliza en establecer unas directrices de diseño de MMICs para la implementación de diversas funciones y aplicaciones, con especial énfasis en su justificación teórica, su aplicación práctica y la validación de los circuitos resultantes de la implementación correcta ya en la primera serie de fabricación. Los circuitos que serán descritos combinan la implementación de funciones lineales (amplificadores) y no lineales (divisores de frecuencia, mezcladores). En los últimos casos las propias técnicas de simulación han sido objeto de un estudio teórico que ha llevado a cabo el desarrollo de interesantes aplicaciones de las herramientas de simulación que pueden explotarse como metodología general de diseño para su aplicación a circuitos no lineales. La tesis cubre tanto aspectos científicos como tecnológicos, orientados a concretas aplicaciones industriales en el sector espacial. De hecho, parte de los resultados conseguidos ha permitido, en el marco de la contribución del grupo de investigación de diseño de MMICs del Departamento de Ingeniería de Comunicaciones de la Universidad de Cantabria, el desarrollo de una nueva generación de transpondedores en banda S que se encuentra en uso en más de 10 misiones espaciales.

This paper presents the design of multifunction monolithic microwave integrated circuits (MMIC) to be used in transmit/receive modules for onboard satellite applications. Two chips have been developed: one for frequency generation including a negatron VCO, a frequency tripler and a digital frequency divider, and a second for signal amplification and conversion including AGC amplifiers and mixers. The goal of the work is to reduce the number and size (and consequently the cost) of the circuitry actually in use, without sacrificing system performance, through the use of a mature GaAs PHEMT technology. Issues such as suitable circuit topologies, dc power consumption, circuit area minimization and optimization are all important factors addressed during the project.

This paper presents the design and performance of a multi frequency generator MMIC to be used in transmit/receive modules for S band transponders. The technology used is a European commercial Enhancement/Depletion (E/D)pHEMT process,compatible with low noise reception.Quasi-monolithic Voltage Controlled Oscillator (VCO),divide-by-four digital frequency divider,active frequency multiplier-by-three and relative power dividers and buffers have been integrated into a single chip to generate all the system frequencies in a flexible architecture. Measured phase noise of the VCO depends on the external resonator and varactor used.Values of –105dBc/Hz@100KHz have been measured with external high Q resonator which is comparable to best performance reported of GaAs based VCOs.The frequency divider by four has an operating window from 30 MHz to >4GHz and an output power of more than 4 dBm.Multiplier by three provides more than 5 dBm in each of the two outputs with adjustable level of harmonics.

A new design method to achieve accurately predictable response in microstrip bandpass filters is presented. Filters are based on conventional coupled line microstrip technology and their frequency range is up to 50 GHz. The design method allows to avoid the inaccuracy of electrical models at these frequencies due to the presence of parasitic effects. Limitations of test procedures using coaxial to microstrip transitions are discussed, and an electrical model for this transition has been obtained. Using a very accurate test method, based on coplanar to microstrip transitions and TRL calibration techniques, it is possible to get a very good agreement between simulation and test results.

The Planck satellite is a mission of the European Space Agency due to be launched in 2007 to map the anisotropies in the Cosmic Microwave Background radiation [1]. These anisotropies hold the answers to many questions in cosmology. Planck receivers are specifically designed to detect microwaves at frequencies in the range between 30 and 850 GHz. Two different instruments are under development to cover low and high frequency channels. The Low Frequency Instrument (LFI) will take measurements in four channels, from 30 to 100 GHz, based on differential radiometers using broadband very low noise amplifiers and direct detection. The Front End amplifiers are cooled at 20 K and the Back End amplifiers are at high temperature. The LFI radiometer system will have a total number of 46 receivers. The Back End Modules at 30 and 44 GHz are in development in Spain, using MMIC amplifiers and Schottky diode detectors. At present the Qualified Model units are under fabrication.

Main technological issues to take into account in the millimetre wave circuits assembly from 27 to 50 GHz are presented: microstrip line circuits and their transitions from waveguide or coaxial, handling and assembly of active devices (transistors and MMIC) and passive devices (capacitors, resistors). Some details of circuits for low noise receivers are shown. RESUMEN: Se presentan los principales aspectos tecnológicos a tener en cuenta en el montaje de circuitos en las bandas de ondas milimétricas entre 27 y 50 GHz: circuitos con líneas microstrip y sus transiciones desde guía de onda o coaxial, manipulación y montaje de componentes activos (transistores y MMIC) y pasivos (condensadores y resistencias). Como ejemplo se muestran algunos detalles de circuitos para receptores de bajo ruido.

This paper deals with the process of realization of a two-stage MIC broadband amplifier in the 44 GHz Band using a commercially available P-HEMT transistor. The attention has been focused mainly on the practical aspects of the fabrication of a hybrid circuit in the millimeter wave band. The problems related with the manufacturing (due to the inevitable tolerances) and its effects on circuit performance are described and analysed.