Beam-scanning leaky-wave antenna based on CRLH-metamaterial for millimetre-wave applications

This paper presents empirical results of an innovative beam-scanning leaky-wave antenna (LWA), which enables scanning over a wide angle from - 35 degrees to + 34.5 degrees between 57 and 62 GHz, with broadside radiation centred at 60 GHz. The proposed LWA design is based on composite right/left-handed transmission-line (CRLH-TL) concept. The single-layer antenna structure includes a matrix of 3 x 9 square slots that is printed on top of the dielectric substrate; and printed on the bottom ground-plane are pi- and T-shaped slots that enhance the impedance bandwidth and radiation properties of the antenna. The proposed antenna structure exhibits metamaterial property. The slot matrix provides beam scanning as a function of frequency. Physical and electrical size of the antenna is 18.7 x 6 x 1.6 mm(3) and 3.43${\lambda }_0$lambda 0 x 1.1${\lambda }_0$lambda 0 x 0.29${\lambda }_0$lambda 0, respectively, where ${\lambda }_0$lambda 0 is free space wavelength at 55 GHz. The antenna has a measured impedance bandwidth of 10 GHz (55-65 GHz) or fractional bandwidth of 16.7%. Its optimum gain and efficiency are 7.8 dBi and 84.2% at 62 GHz.