Miniaturized tunable artificial magnetic conductor for low LTE band

Antennas operating in the lower band of the LTE spectrum (700-960 MHz) have conventionally required thicknesses around a hundred millimeters when placed over metallic reflectors. Miniaturized Artificial Magnetic Conductors (AMC) metasurfaces have been shown to reduce the profile (height) of these antennas while maintaining compact lateral dimensions, but at the expense of operating bandwidth. Adding tunability restores the possibility of adjusting the operating frequency over a large bandwidth. In this paper, a highly miniaturized and tunable AMC covering the lower LTE band is proposed. The novel unit cell achieves an 83 % reduction in the largest dimension compared to conventional unit cell at the highest frequency f0=960 MHz. Simulation results show that the proposed AMC surface has the potential to be used with either tunable or broadband low profile electrically small antennas.