A compact offset CPW-fed dual polarized stubs loaded monopole antenna for quad-band operation

Abstract

A compact offset coplanar waveguide (CPW)-fed dual polarized stubs loaded L-shaped branch monopole antenna for quad-band operation is presented. A resonant mode at 2.48 GHz is generated by adding an inverted L-shaped branch in the offset CPW-fed monopole and other three resonant modes at 3.41/4.96/7.45 GHz are generated by integrating asymmetrical long/middle/asymmetrical inverted short L-shaped stubs at different locations vertically on inverted L-shaped branch monopole, respectively. The proposed antenna provides impedance bandwidths (IBWs) of 140 MHz (2.40–2.54 GHz), 460 MHz (3.22–3.68 GHz), 170 MHz (4.89–5.06 GHz), and 840 MHz (7.09–7.93 GHz), for 2.4 GHz Bluetooth/WLAN, 3.5 GHz WiMAX, 4.9 GHz public safety WLAN, and downlink of X-band satellite applications, respectively. It also exhibits circular polarization (CP) in the X–band and having axial ratio bandwidth (ARBW) of 300 MHz (7.25–7.55 GHz). It is designed on FR-4 substrate and occupies a compact size of 14.5 mm × 26.5 mm. It is also analysed that the individual band can be tuned independently by varying their respective dimensions of stubs.