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Title: Novel microwave devices based on multi-port filtering networks
Author: Ogbodo, Eugene Amobichukwu
ISNI:       0000 0004 7963 382X
Awarding Body: University of Greenwich
Current Institution: University of Greenwich
Date of Award: 2017
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This thesis is based on the novel device concept of Multi-Port Filtering Networks (MPFNs). This is a concept derived from conventional two-port filters to link two or more filters in communication systems. It is interesting to the microwave filtering component designers as it reduces the footprint, cost and structural size. One potential application of this concept is diplexers/multiplexers. The conventional structure of joining two or more filters using the transmission based line junctions or circulators is eliminated. It is replaced by a common resonant junction which also contributes to the resonant poles of filtering network. In this thesis, the methodology for MPFNs is developed and a number of microwave filtering components are designed and results presented. It starts with a comparative study between the conventional diplexer and a resonant junction diplexer in terms of performance, size, and power handling capabilities. It was found that the resonant junction diplexer is more compact with slightly higher power handling capability. Some number of diplexers were presented using the MPFNs technique. Various dual-mode resonators such as the patch, the split-ring-resonator and the asynchronously-coupled-junction were implemented as the junction of the diplexers. All demonstrated the signal distribution and combining functions. The demonstrated techniques resulted in a more compact diplexer circuitry without sacrificing the selectivity of the channel filters. As the building block of a diplexer or a multiplexer, this thesis also proposed and demonstrated several single-band or dual-band filters. In particular, the mixed use of single and dual-mode resonators has shown the capability and flexibility to improve the frequency selectivity by controlling the transmission zeros. Dual mode resonators were also used to split and combine the signals in dual-band designs as in the diplexers. This thesis has started exploring and examining the new idea of multi-input and multi-output filters in the framework of MPFNs. Several four-port filtering networks were investigated. And finally, as an extension and slightly diversion of the work, the integration of a duplexer and an antenna based on an all-resonator structure was studied using the co-design approach essentially based on filter designs.
Supervisor: Wang, Yi ; Callaghan, Peter ; Kyberd, J. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TK Electrical engineering. Electronics Nuclear engineering