Abstract: This paper proposes a two-dimensional (2-D) beam-scanning array fed by a broadband Butler matrix with four composite right/left-handed (CRLH) substrate integrated waveguide (SIW) leaky-wave antennas. The 2-D beam scanning is achieved by varying the operating frequency and switching the input ports of the Butler matrix respectively. The proposed array is fabricated and measured. The measurement results demonstrate that frequency agility from 3.7 to 4.7 GHz enables continuous scanning from -60° to 66° in the azimuth plane. Moreover, switching the feed ports produces four discrete beams (-36°, -12°, 16°, and 36°) in the orthogonal azimuth plane. With its wide upper-half-space coverage, low cost, and low profile, the proposed array has the potential for structure-embedded applications.