Wearable textile patch antenna fed by proximity coupling with increased bandwidth

This letter presents the design methodology of a textile rectangular patch antenna with increased bandwidth. The broadening of the antenna operating band is obtained by using a proximity coupling feed line cascaded to a quarter-wave impedance transformer. The design parameters used to enhance the antenna bandwidth are the widths of the feed line and impedance transformer. The proposed design procedure has been applied to the design of four antennas centered at 2.45 GHz using denim substrate and conductive fabric. All antennas have the same patch dimensions, but they were designed using different values for the widths of the feed line and impedance transformer. The measured 10-dB return loss bandwidth of the antenna prototypes are 11.2%, 13.4%, 17.0%, and 24.0%, in good agreement with simulated results. The effect of human body proximity and antenna curvature on the performance of the designed antennas has also been analyzed. The antenna configuration investigated has demonstrated to be able to increase the antenna operating band. The proposed design procedure is flexible, allowing the design of antennas with a variety of bandwidth values. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1906–1912, 2016