A Floral-Like Fractal Ultra-Wideband Flexible Antenna for Wearable Device

In the context of the rapid development of wireless body area network and ultra-wideband technology, this design puts forward a new structure of ultra-wideband flexible antenna. Its operating band is 1.22–8.82 GHz, with a maximum gain of 4.8 dBi. The antenna adopts a polyimide material with a relative dielectric constant of 3.5 and a thickness of 0.2 mm as the dielectric substrate. The overall size of the antenna is very small, measuring 0.15λ × 0.21λ at the lowest frequency of 1.22 GHz. In this paper, the influence of some antenna parameters on its performance, the influence of different bending conditions on the performance of the antenna, and the specific absorptivity of the antenna to the human body are discussed. In order to further explore the performance stability of the antenna, the performance of the antenna under right-angle bending is simulated and tested in this paper. Simulation results show that the antenna still has two frequency bands 1.22–2.58 GHz and 3.35–9.53 GHz under right-angle bending, which can still cover most of the commercial communication bands, and the measured results are in good agreement with the simulation results. Therefore, the antenna has strong adaptability and damage resistance and can be used in wearable equipment for military or emergency rescue.