Beam focusing compact wideband antenna loaded with mu-negative metamaterial for wireless LAN application

Abstract

This article proposes a beam focusing compact wideband microstrip antenna loaded with mu-negative (MNG) metamaterials. The antenna is designed to operate in the frequency spectra of IEEE 802.11a wireless LAN 5.15–5.85 GHz. The controlling of the beam direction has been investigated using eight different switching combinations of 12 PIN diodes which are integrated in the metamaterial unit cells. The main beam is found to be focused in −vey, +vey and omnidirectional in yz plane in agreement with switching condition of the metamaterial unit cell. The maximum gain enhancement of 7 dB is obtained at 4.9GHz in the negative y direction. The basic antenna with patch dimension (0.14λ×0.14λ) provides wide fractional bandwidth of about 40%. Two prototypes of basic and proposed antennas have been developed using a low profile FR-4 substrate. The simulation results are found in good agreement with the measurement ones.