A metamaterial antenna with programmable spatial and transient radiation beams by using monolithically integrated RF-MEMS switches

In this paper, we report for the first time a programmable active metamaterial leaky-wave antenna using a monolithically integrated MEMS (microelectromechanical systems) switch array. The metamaterial antenna is integrated with surface micro-machined capacitive switches that could be electrostatically actuated to alter the electrical conditions in the antenna units by the external voltages supplied through the bonded-wires. Due to the discrete periodical metamaterial units that can be independently controlled, the equivalent propagation constant β of the antenna is manipulated to spatially modulate the radiation patterns, thereby enabling programmable antenna performances. Furthermore, we discuss and analyze the spatial and the transient resolution of the radiation for the first time, by which continuous spatial scan is synthesized from discrete periodical antenna patterns of digital control. Given the number of units, the scan speed is found to depend on the electromechanical resonant frequency of the MEMS modules. Experimental results on a 5-bit programmable antenna agree well with the analytical simulations.