A High-Power Sandwiched Omnidirectional Circularly Polarized Antenna for GNSS Systems

This paper presents a small-size, low-profile antenna for anti-attacking systems that work against unmanned GNSS-guided attacking vehicles to protect a vital area. The proposed antenna has the ability to handle, theoretically, a peak power up to 157.7 kW. It has a cylindrical shape with a diameter of 75.4 mm and a height of 12.8 mm on a low-cost FR-4 substrate. This small size allows the integration of the proposed antenna with any portable system that prevents the attacks of GNSS-guided vehicles. The proposed antenna covers the whole GNSS frequency band with a fractional impedance bandwidth of 32.5% (1.16–1.61) GHz and a fractional axial ratio bandwidth of 37.6% (1.1–1.61) GHz utilizing a sandwiched structure. This broadband performance is realized using capacitive feeding. The proposed design maintains circularly polarized radiation over a wide elevation angle of 132° and a 360° azimuth angle which makes the proposed design suitable for GNSS anti-attacking systems.