CPW-Fed Dual-Band Linearly and Circularly Polarized Antenna Employing Novel Composite Right/Left-Handed Transmission-Line

A coplanar waveguide (CPW)-fed dual-band antenna operating at linear and circular polarization is presented in this letter. A novel composite right/left-handed (CRLH) unit cell is designed as a radiation element that can provide zeroth-mode resonance and positive-mode resonance at the lower and upper frequency. A TM₀₁ mode orthogonal to +1st-Order is excited by a square complementary split-ring resonator (S-CSRR) in order to form a circular polarization. The equivalent circuit model is applied to analyze and design the CRLH unit cell. The antenna has a linearly polarized slot-like radiation characteristic at the lower frequency and a circularly polarized patch-like radiation characteristic at the upper frequency. Also, the total electrical size of the fabricated dual-band antenna employing a single unit cell was 0.14λ₀ ×0.16λ₀ ×0.01λ₀ at the lower frequency. Simulation and experimental results are used to verify the theoretical prediction .