Beam-Steering Antenna using Bending Fluidic Actuators

A beam steering antenna is described which uses bending parasitic elements controlled by bending fluidic actuators (BFAs). The structure is a monopole antenna surrounded by four parasitic elements on a groundplane. The BFAs are controlled by linear controllers located below the groundplane. In this way, the parasitic elements comprise BFAs and the action of bending them away from the monopole to alter the mutual impedances is analogous to the reactance variation of switched parasitic antenna. When a parasitic element is not bent, it can act as a reflector or director for low-gain beam formation, while the other parasitic element is bent away from the monopole and hence not affecting the beam. Two configurations have been realized with different numbers of bent parasitic elements, and experimental results for these configurations are presented. Patterns with low cross correlations can be attained while keeping the return loss below a reasonable limit.