A small-size zeroth-order resonating antenna based on a composite right/left-handed transmission line (CRLH TL) fabricated on high resistivity silicon substrate using coplanar waveguides (CPW) is proposed. The CRLH TL consists of a series of CPW interdigital capacitors and parallel short-ended CPWs. The predicted and experimental results for return loss, gain and radiation pattern are in very good agreement.Introduction: A possibility to implement meta-materials is to use artificial composite right/left-handed transmission lines (CRLH TLs)[1]. The CRLH TL is the key to a new class of devices such as backward-wave directional couplers [2], leaky-wave antennas [3, 4] and zeroth-order resonating antennas [5]. All CRLH TL based circuits reported to date involve microstrip lines and hybrid technology. To integrate monolithically these circuits, together with other passive or active devices, they must be designed on a semiconductor substrate, using coplanar waveguide (CPW) configurations. In this Letter, the design, fabrication process and measurements for a CPW CRLH TL based zeroth-order resonating antenna realised onto a silicon substrate are presented. Using CPW lines, the area occupied by the antenna could be further reduced compared with the microstrip CRLH TL based antenna [5], because the virtual-ground capacitors are no longer necessary.