A Compact Dual-Band Dual-Polarized Omnidirectional Antenna for On-Body Applications

A compact dual-band dual-polarized wearable antenna for on-body communication in the 2.45 and 5.8 GHz ISM bands is presented. The antenna is linearly polarized (LP) at 2.45 GHz and circularly polarized (CP) with the conical pattern at 5.8 GHz, which is suitable for the multisensor link network. By using the characteristic modal analysis initially, the ground plane has been miniaturized and optimized to radiate an omnidirectional beam in the horizontal plane with the excitation of the lambda/4 resonant mode. The higher order band at 5.8 GHz has been realized by the excitation of the 3 lambda/4 resonant mode of the same L-shaped slot. These two odd-order modes radiate horizontally polarized omnidirectional patterns. The combination of the vertical polarization generated from the top-loaded patch antenna along with the 3 lambda/4 mode from the L-shaped slot resulted into omnidirectional CP in the 5.8 GHz band. Furthermore, enhancement in axial ratio bandwidth is achieved with the addition of dielectric superstrate over the feed layer. Bending sensitivity study to emphasize for conformal applications, transmission loss along with specific absorption rate analysis has been performed for on-body characterization. The simulated and measured results are found to be in good agreement.