Flexible Wearable Spiral Antenna Applied to Narrowband Internet of Things Range

This work proposes the development of a flexible wearable spiral printed circuit board antenna, shaped like the letter P, for use in the narrowband Internet of Things, which can be used to capture electromagnetic energy, operating in the 880 MHz band. The antenna is designed and built in polyamide laminate, a flexible dielectric, consisting of three 0.5 mm thick transmission lines, separated by a distance of 1 mm, connected to a transmission line, and a ground plane in the same plane as the antenna, with impedance matching promoted by the distance between the ends of the lines and the antenna structure. The use of the three transmission lines, and the distance of and twice the transmission line promote stability in the main parameters of the antenna. From the results it was observed that the printed circuit board spiral wearable P-shape antenna obtained an omnidirectional radiation pattern, resonance frequency measured at 877 MHz, measured narrowband, with bandwidth of 20 MHz, half-power beam width of 108º, maximum gain of 5.5 dBi and current density of 6.93 A/m ² , and compact structure, 5.47 cm ² , with characteristics for use in capturing electromagnetic energy from incident waves from distant radiators or nearby circuits.