Narrow-beamwidth T-shaped monopole antenna fabricated from metamaterial wires

A simple T-shaped monopole is converted into a metamaterial antenna by loading lumped capacitors and inductors on the metal wire. The new metamaterial antenna could sustain a half-wave resonance even when its length exceeds several free-space wavelengths. An 80 mm-long monopole initially resonating at 1.3 GHz is modified to operate at 3.6 GHz with a reduced 3 dB H-plane beamwidth of 48deg.