A compact CPW-fed dual-band open-ended ZOR antenna based on CRLH TL for wireless applications

摘要

A compact CPW-fed dual-band open-ended zeroth order resonance (ZOR) antenna with the partial backed ground plane is investigated. The designed antenna comprises of a patch on which interdigital capacitor imposed on a patch, a thin stripline, which is connected with slotted stub and at bottom a rectangular patch connected with partial ground plane via thin inductive strip. By using the rectangular patch on the ground, the proposed antenna is able to generate dual bands, which satisfy the required bandwidth for wireless communication systems. The interdigital capacitance and gap between patch I and patch II forms an equivalent series capacitor (Cn_Leqn) while combine effect of top and bottom strip line forms shunt inductance (Ln_Leqn) which verifies the composite right/left-handed transmission line based on metamaterial MTM). The shunt capacitance (Cn_Rn) is obtained between partial backed ground plane and CPW feed, whereas the series inductance (Ln_Rn) is realized by signal patch. Presented antenna follows open ended boundary condition, so ZOR frequency depends on shunt components. The proposed dual-band MTM antenna with rectangular stub exhibits a simulated input impedance bandwidth (Sn₁₁n<; -10 dB) of 10.08% (1.13-1.25 GHz) for the first band and 35.79% (3.44-4.94 GHz) for the second band, respectively. The electrical size of designing antenna is 0.1 λn₀n× 0.16λn₀n× 0.0064λn₀nwhere λn₀nis free space wavelength indicates its compactness. It is observed that at ZOR frequency (1.2GHz) and other frequency (3.9GHz), the proposed antenna showing dipolar type radiation pattern in xz-plane whereas in yz-plane it shows omnidirectional radiation pattern. The difference between co- and cross-pol levels in xz-plane is -41.6dB at ZOR frequency. In addition, the dual-band MTM antenna offers good gain and radiation efficiency in the working band which is useful for modern wireless communications such as L/S and C band applications.