Efficient dual-band PIFA antenna for the Internet of Things (IoT)

in this paper, the design and optimization of an efficient dual-band Planar Inverted-F Antenna (PIFA), more adapted to the operation in a complex environment and working in the unlicensed 868 and 915 MHz ISM bands for IoT applications in Europe and USA are presented. It consists of a metal plate whose length has been optimized to work at a frequency of 915MHz and to which a second plate charged with a capacitor of 0.8pF has been added to create a second resonance at the frequency of 868MHz. The dimensions and positions of the short-circuit and the feeding strip of the PIFA have been optimized to maximize the radiation efficiency of the antenna. A good impedance matching and high radiation efficiency were obtained in both 868 and 915 MHz frequency bands.