A Novel Compact Wideband Planar Inverted-F Fishbone Antenna with Load-Bearing Capacity and Its Application in CP Array

A novel compact wideband load-bearing planar inverted-F fishbone antenna (PIFFA) element and a circularly polarized (CP) unit based on PIFFA are proposed. The main radiator of the PIFFA is a folded fishbone structure with dimensions of 0.14λ ₀ × 0.19λ ₀ × 0.15λ ₀ , which is excited by a monopole. It works in hybrid mode dominated by odd mode, which realizes directional radiation. The PIFFA has an available bandwidth of 1.29 - 2.46 GHz (62.4%), and gain ranging from 3.98-5.76 dBi. Four PIFFA elements are rotationally symmetric arranged around the center and construct the compact CP unit. The measured operating bandwidth of the CP unit is 1.18-1.91 GHz (47.2%) and the gain ranges from 6.2-8.6 dBi. It is noted that the CP unit can bear the load of 1000 kg/cm ² without clear performance deterioration. In addition, four CP units are extended to form a linear one-dimension array with broadside dual circular polarization beam scanning capability. The one-dimension array achieves CP scanning range of ± 61° at 1.25 GHz in experiment. These results demonstrate that antennas designed with a folded fishbone structure have excellent performance and practical value, making them suitable for a wide range of high-speed wireless communication systems.