Abstract

This paper presents a low-profile textile scorpion patch antenna for wearable applications. The modal behaviors of the proposed antenna are investigated by using the theory of characteristic modes analysis (CMA). Four characteristic modes with the same resonant frequencies and orthogonal current distributions are chosen for operation. The proposed antenna has a simple structure with an overall size of 0.74 λg × 0.74 λg × 0.06 λg (guided wavelength at 5.5 GHz). This work characterizes and estimates the final shape of the patch using the CMA method aimed at obtaining the required resonant frequency. The shape optimization is simplified, as the substrates’ influence and excitation are first excluded. This optimizes the needed time and resources in the design process, in contrast to the conventional optimization approaches made using full-wave “trial and error” simulations on a complete antenna structure. A systematic investigation of the effects of bending applied on wearable patch antennas over cylindrical surfaces is presented via extensive simulations performed using FEKO software based on both the CMA and the Method of Moments (MoM). The measurement results show that the proposed antenna has -10 dB impedance bandwidth of from 4.8 to 5.59 GHz. Moreover, the simulation results indicate that the antenna gain of 3 dBi over the whole operating bandwidth.