The ever increasing diversity in communication systems has created a demand for constant improvements in receiver components. This thesis describes the design and characterisation of front-end receiver components for various challenging applications, including characterisation of low noise foundry processes, LNA design and multi-band antenna design. It also includes a new theoretical analysis of noise coupling in low noise phased array receivers.In LNA design much depends on the choice of the optimum active devices. A comprehensive survey of the performance of low noise transistors is therefore extremely beneficial. To this end a comparison of the DC, small-signal and noise behaviours of 10 state-of-the-art GaAs and InP based pHEMT and mHEMT low noise processes has been carried out. Their suitability in LNA designs has been determined, with emphasis on the SKA project. This work is part of the first known detailed investigation of this kind. Results indicate the superiority of mature GaAs-based pHEMT processes, and highlight problems associated with the studied mHEMT processes. Two of the more promising processes have then been used to design C-band and UHF-band MMIC LNAs. A new theoretical analysis of coupled noise between antenna elements of a low noise phased array receiver has been carried out. Results of the noise wave analysis, based on fundamental principles of noisy networks, suggest that the coupled noise contribution to system noise temperatures should be smaller than had previously been suggested for systems like the SKA. The principles are applicable to any phased array receiver. Finally, a multi-band antenna has been designed and fabricated for a severe operating environment, covering the three extremely crowded frequency bands, the 2.1 GHz UMTS, the 2.4 GHz ISM and the 5.8 GHz ISM bands. Measurements have demonstrated excellent performance, exceeding that of equivalent commercial antennas aimed at similar applications.

L’augmentation du nombre d’appareils communicants et du débit de données a pour conséquence une montée en fréquence des dispositifs micro-ondes, notamment dans le secteur du spatial. L’optimisation des modules existants n’est pas toujours suffisante. Il faut donc synthétiser de nouveaux circuits. Cependant, la plupart des méthodes de synthèse existantes, inclues dans les logiciels de CAO, ne prennent pas en compte les modèles à pertes des fondeurs. Or, plus la fréquence de fonctionnement est élevée, plus leurs prises en compte est indispensable. Cette thèse propose une nouvelle méthode de synthèse et de conception pour les circuits faible bruit intégrés (amplificateur faible bruit et mélangeur). Elle prend en compte les modèles à pertes des composants passifs des fondeurs, les lignes de connexion, les jonctions et elle combine plusieurs fonctions comme l’amplification et le filtrage ainsi que le mélange et le filtrage. Elle a été validée en simulation et en mesure. / Due to the evolution of wireless systems and data rate, it is necessary to increase microwave operating frequencies, especially in space industry. Optimization of existing circuit topologies are always not enough and therefore, we need to synthetize new circuits. Unfortunately, most of the existing synthesis methods, including in CAD softwares, are only based on lossless passive component models. With the increase of operating frequency, we need to take the effect of losses in the passive component models during synthesis. This thesis introduces a new synthesis and design method for low noise integrated circuits(low noise amplifier and mixer). Lossy passive component models from foundries, connecting wires, junctions and co-design (amplification and filtering or mixing and filtering)are included. The design procedure was validated by simulations and measurements.