An Active Metamaterial Antenna With MEMS-Modulated Scanning Radiation Beams

In this letter, for the first time, we report a microelectromechanical system (MEMS)-modulated scanning beam metamaterial antenna based on surface micromachining process. The antenna is implemented by cascading periodical metamaterial modules with a unit length of less than λg/5 to make an electromagnetically homogeneous waveguide, of which the MEMS cantilevers are monolithically integrated in each unit as a radio frequency (RF) switch to modulate the phase constant β, and thereby to realize the scanning beams in the fixed frequency around 8 GHz. Experiments that verified the MEMS-modulated scanning radiation beams are tuned from the backward (around -15°) to the broadside (around 0°) and to the forward (around +15°) directions as the RF-MEMS switches are, respectively, actuated from the states of 0000-0000 (switches in all of the eight units are OFF) to 1010-1010 (switches in the unit of numbers 1, 3, 5, and 7 are ON) and to 1111-1111 (all switches are ON).