This paper presents a simple and compact coplanar waveguide (CPW)-fed circular-shaped reconfigurable patch antenna with a switchable circular polarization (CP) sense. The circular patch is cut at the ends vertically and switches are introduced to connect the patch ends. By controlling the ON/OFF status of the two switches, the polarization of the antenna can be switched between two states: left-hand circular polarization and right-hand circular polarization. The patch is designed on a very thin RT Duroid substrate of dielectric constant (εr) of 2.2 and thickness of 0.254 mm. The overall antenna dimensions are 35 × 30 mm. The antenna is designed and simulated using finite-element method -based EM simulator, HFSS. For each switching condition the return loss curve, radiation pattern are obtained. Axial ratio curves for polarization diversity cases are also plotted. Parametric studies have been made in order to get optimized values for certain antenna dimensions such as thickness, CPW ground to feed gap, etc.

Index Terms-CPW feed, frequency diversity, patch antenna, reconfigurable antenna.

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This paper presents a novel, compact and simple reconfigurable antenna using coplanar waveguide feed which has frequency, polarization and pattern diversities. The basic antenna consists of four rectangular patches of dimensions 5 mm × 4 mm. Three switches are used to connect these four patches and with different switching modes, the desired reconfigurability is achieved. The operating frequency/band can be selected as 5.15 GHz (with 33.6% of impedance bandwidth) or 5.55 GHz (with 55% of impedance bandwidth) in two different operating modes. Reconfiguration in polarization takes place from linear polarization to right hand circular polarization and left hand circular polarization, and antenna is capable of rotating its radiation beam by ±180°. The measured results are in good agreement with simulated ones. The antenna exhibits good return loss characteristics, acceptable gain and VSWR.