Miniaturised planar‐patch antenna based on metamaterial L‐shaped unit‐cells for broadband portable microwave devices and multiband wireless communication systems

This study describes the design of a metamaterial planar antenna for multi‐octave band operation. The metamaterial unit‐cell comprises L‐shaped slit which is etched inside a rectangular patch with a grounded inductive spiral. The slit essentially behaves as a series left‐handed capacitance and the spiral as a shunt left‐handed inductance. The antenna was modelled and optimised for impedance bandwidth, gain and efficiency performance using commercial three‐dimensional full‐wave electromagnetic simulation tools. The antenna has a measured impedance bandwidth of 6.02 GHz for S 11 <−10 dB. This corresponds to a fractional bandwidth of 172.49%, which is higher than multiband planar antennas reported to date. The antenna has a maximum gain and efficiency performance of 3.7 dBi and 73%, respectively, at 3.25 GHz. The physical footprint of the antenna is comparable to other wideband planar antennas reported to date. The overall size of the antenna is 0.037 λ 0 × 0.027 λ 0 × 0.002 λ 0 and 0.25 λ 0 × 0.18 λ 0 × 0.017 λ 0 , where λ 0 is free‐space wavelength at 0.48 and 3.25 GHz, respectively.