RF and Microwave Systems

Future Radio Systems

 

The research activities in this area encompass both network and transceiver link level issues. A key factor in the design and performance of any wireless communication system is the transmission medium. Link losses will determine operating range whilst multipath dispersion can give rise to fading and intersymbol interference, requiring anti-multipath techniques such as equalisation and diversity. In a cellular communication system, the BS-MS link is not only affected by its own RF channel but also from co-channel and adjacent channel signals (and their associated RF channels). Further, in CDMA systems, power control is a key issue in optimising capacity.

Thus, in order to optimise capacity (with due regard to deployment costs), knowledge of the propagation medium is required. A parametric analysis of network capacity as a function of planning uncertainties (i.e. incorrect assumptions regarding channel behaviour) for second generation systems was been undertaken as part of a PhD thesis (supported by BT Labs under the VURI on Mobility). In parallel with this activity, a number of channel measurement systems have been developed to support fundamental electromagnetic propagation research at the University of Birmingham with the group headed by Dr. Costas Constantinou. Field measurements taken by the Oxford/VURI team have also been used by VURI members at the University of Bristol in assessing UMTS microcellular performance. Click here for more details on Future Radio Systems.

Advanced RF Microwave Devices

The Advanced Devices Group has the primary objective of investigating fundamental technological and materials advances and their application to Communications Technologies.

Thin and thick films of the thallium-based HTS are deposited on a variety of substrates, with and without buffer layers, in collaboration with the Department of Materials. Microwave characterisation of these films is carried out, over the frequency range 1-40 GHz, by cavity end wall replacement, parallel plate, dielectric resonator and confocal resonator techniques. Devices such as delay lines, antennae, free space mixers, filters, resonators and an integrated hybrid voltage controlled oscillator have all been successfully operated at 77K and demonstrated to have performance superior to similar devices implemented in copper or silver. Work is continuing on the development of disc resonators and filters, and hybrid circuits and sub-systems for microwave communications. Applications include digital signal processing and CDMA spread spectrum systems. The engineering of a system/cryocooler package is investigated in collaboration with the Cryogenics Group.

The Advanced Devices Group activities of the Communications Group, the Materials Department and the Cryogenics Group (all at Oxford University). Click here for more details on Advanced RF/Microwave Devices.

Radar Systems and Antennas

On-going projects within this research area include:

     antennas

       A selection of microwave printed circuits designed and fabricated in-house. 

 

Click here for more details on Radar Systems and Antennas.

 

Submarine Electromagnetics

A Knowledge Transfer Partnership provided the basis to develop a new research theme in underwater Electromagnetics· 

Click here for more information.