Reconfigurable and Integrated Antennas for Cognitive Radio

Cognitive radio (CR) is a revolutionary technology that aims for remarkable improvements in efficiency of spectrum usage. Originating from the concept of software defined radio (SDR), CR can be viewed as an extension of SDR in terms of environmental awareness. Basically, CR relies on a radio being able to sense whether a particular band is being used and, if it is not, to utilise the spectrum without interfering the transmission of other authorised users. If the primary user returns to the same band for transmission, the radio switches to another band, or stays in the same band, modifying its transmission power level or modulation scheme to avoid interference. Such agility to adapt or to change allows such the radio to perceive the world around it and learn from experience. Although the software and intelligence requirements of such a network have yet to be defined, the implications on the radio itself pose tremendous challenges. To achieve this capacity for spectrum agility, optimising for power, modulation, range and other communication parameters, an extremely flexible RF front end is vital. As such, the antenna front end challenges are immense, which are addressed in this proposal.