A novel realisable dual composite right/left-handed (D-CRLH) coplanar waveguide (CPW) transmission line(TL) in GaAs MMIC technology demonstrated by theoretical analysis and experimental results is presented. A D-CRLH TL is the dual of the conventional CRLH TL in the sense that it consists of series LC parallel tanks and shunt LC series tanks. However, an ideal D-CRLH TL cannot be realised because of unavoidable parasitic effects. The measured results indicated that a real D-CRLH TL exhibits a fundamentally different frequency response at higher frequency band in that a real D-CRLH TL cannot provide unlimited left handed (LH) bandwidth. Instead, it has triple bands; right-handed (RH) passband at lower frequencies (DC-2.9 GHz), LH passband at intermediate frequencies (5.1–14.3 GHz) and RH passband at higher frequencies (above 14.3 GHz). The reported fully integrated D-CRLH CPW TL metamaterial has a very compact size of 2.2 mm2 which leads to a small loss 1.5 dB within 3 dB LH passband.