Scanning-beam antenna on metamaterials coplanar structure for wireless applications

A scanning-beam antenna on metamaterial coplanar structures is presented. The proposed antenna is, in essence, a composite of Right/Left-Handed (CRLH) coplanar waveguide (CPW) structure incorporating distributed periodic structures with L-C high-pass filter topology which support left-handed (LH) waves. The negative refractive index (NRI) properties of these structures are shown theoretically, numerically and validated by full-wave simulations. The supported LH wave is fully characterized and based on the composite right/left-handed transmission-line (CRLH-TL) theory; and the dispersion characteristics, refractive indexes and Bloch impedance are derived theoretically. In addition, formulas to extract equivalent-circuit parameters from full-wave simulation are given. Since the distance d between adjacent cells of the array is small, d < < λo and the array becomes a uniform leaky-wave antenna (LWA) for a 10-cell operating near 10 GHz. Simulated radiation pattern, gain, and associated loss budget are presented. The results of LWA exhibit scanning-beam capability from backfire-to-endfire direction and accord well with the theoretical analysis. The antenna is printed on thin and flexible substrate (h = 25 μm). Furthermore, since the antenna is implemented with low-cost and CPW technology, it is a good candidate for integrated RF/microwave systems that can be used in digital wireless communications and radars.