Ultra-wide band flexible antenna applicable for dual-band on-body communications

In this article, an ultra-wideband printed flexible monopole antenna is proposed for indoor wireless communications. A flexible Rogers RO3003 is used as a substrate, and its performance is estimated for a flat state and when subject to bending along the y-axis. A 2.45 and 5.8 GHz dual-band textile artificial magnetic conductor (AMC) surface consisting of a 4 x 4 unit-cell array was integrated into antenna design with optimum separation distance to extend its potential applications to wearable on-body communications. The specific absorption rate (SAR) levels were numerically investigated using the Hugo human voxel model at both frequencies to evaluate the on-body safety level. Detailed analysis is presented for antenna designs of flat and bent states in free space and on the human body. The proposed UWB flexible antenna has the size of 41 x 38 x 0.25 mm (0.33 lambda(0) x 0.31 lambda(0) x 0.002 lambda(0) at 2.45 GHz). It was added at a distance of 3 mm above a textile AMC surface of 99 x 99 mm. The integrated model is fabricated and experimentally characterized. Measured data and numerical results show that the impedance matching and radiation characteristics are slightly affected by introducing the bending and human body loading. With these remarkable features, the integrated model can be utilized for wireless indoor and wearable applications.