Circular polarized textile antenna

Abstract

Recently, wearable electronic applications have arising in the commercial market. There has been growing use of textile antennas for wearable electronic and body centric applications such as healthcare, GPS and fire fighter personal communications. The use of circularly polarized antennas presents an attractive solution to achieve this polarization match which allows for more flexibility in the angle between transmitting and receiving antennas The new generation of textile has the capability to conduct electricity and at the same time as wearable. Microstrip patch antennas represent one family of compact antennas that offer a conformal nature and the capability of ready integration with communication system’s printed circuitry. In this project, a circular polarized (CP) textile antenna is designed and simulated at 2.4GHz. To achieve circular polarization an inverted z slot asymmetrical structure is introduced at the center of radiating element, once incorporated onto the square patch two orthogonal components of electric field are excited with a 900 time phase difference. Both the patch and the inverted z slot were adjusted such that the wearable antenna generates the circular polarized wave at the resonance frequency. The proposed antenna has a dimension of 50mm x 50mm x 0.035mm, made by the use of fleece textile material as a substrate with a thickness 1mm, dielectric constant 1.3 and loss tangent 0.024. The antenna is fed via a subminiature version A (SMA) connector. The simulated and measured result shows that the antenna offers approximately 6.7% bandwidth (2.42GHz-2.59GHz) return loss, S11 is -32.16dB with impedance bandwidth of 167 MHz and The flexible antenna has axial ratio bandwidth of 80 MHz i.e 3.25% covering the frequency range of (2.42GHz -2.5GHz). The antenna has a good performance in term of axial ratio.