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° to + 34.5° 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 × 9 square slots that is printed on top of the dielectric substrate; and printed on the bottom ground-plane are Π- 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 × 6 × 1.6 mm3 and 3.43λ0 × 1.1λ0 × 0.29λ0, respectively, where λ0 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.