A novel broadband AMC surface for lowering the height of planar antennas

A novel broadband artificial magnetic conductor (AMC) surface is proposed for lowering the height of planar antennas. By replacing the conventional perfect electric conductor (PEC) ground plane with the AMC surface, the height of planar antenna can be significantly reduced. Three planar antennas for LTE700/GSM900 base stations are investigated. The antenna height is lowered from 0.263λ_0.83GHz to 0.083λ_0.83GHz, (where λ_0.83GHz is the wavelength in free space at the frequency 0.83 GHz). The height-lowered planar antennas maintain a wide bandwidth of, e.g., 38% for a linearly polarized antenna, 35% for a dual-polarized antenna, and 46% for a circularly polarized antenna. All these planar antennas above the AMC surface have a gain of higher than 7 dBi.