Smart microwave materials and structures

Smart electromagnetic structures are ones which can sense their electromagnetic environment and reconfigure themselves according to some prearranged requirement so as to appear as either a window, an absorber or a reflector. As such, they incorporate components for sensing, feedback/control and reconfiguration. Applications include radar signature control, smart anechoic test facilities and co-operative reflectors.

With support from EPSRC and QinetiQ, we are investigating suitable smart structure topologies and the functional materials needed for their operation. Materials under investigation are based on microparticulate and nanocomposite conducting polymers with a suitable redox couple in a polymer electrolyte matrix. They show large, rapid and fully reversible changes in their microwave properties when small d.c. or low frequency a.c. fields are applied.

Microwave transmission coefficient with (top) and without (bottom) an applied field of 12V