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Title: Front-end considerations for next generation communication receivers
Author: Roy, Mousumi
ISNI:       0000 0004 2739 9023
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2011
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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.
Supervisor: George, Danielle Sponsor: UKIERI - UK India Education and Research Initiative
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Square Kilometer Array ; Transistor characterisation ; HEMT ; Transistor noise parameters ; Transconductance ; Broadband LNA ; Broadband Low Noise Amplifier ; C-band MMIC LNA ; UHF-band MMIC LNA ; MMIC ; Noise coupling in phased array antennas ; Phased array systems ; Multiband antennas ; MPA ; Microstrip Patch Antenna ; Antennas for process industry ; WSN ; WLAN ; Wireless Sensor Network ; pHEMT ; mHEMT ; SKA