Low profile bearable UHF/L dual-band CP directional antenna in a shared aperture

The airborne/vehicle multi-system communication, measurement and control, detection and other multi-wireless systems coexist, multiple antennas are scattered correspondingly, and the interference between the antennas are serious. Meanwhile, the airborne/vehicle conformal antenna needs to have strong carrying capacity. This paper designs a low profile bearable dual band CP directional slot antenna suitable for car shells in a shared aperture. The antenna body adopts the form of open slots to realize the miniaturization and broadband performance, and the microstrip line is used to feed the slot via the coupling. The shared aperture dual band antenna is realized by slotting and embedding high-frequency antenna in the low-frequency antenna. The circular polarization is realized by using the multi-feed method. The antenna is filled with substrate FR4, the maximum thickness of which is 5% of the wavelength corresponding to the lowest frequency. This hybrid metallic and dielectric stereoscopic structure greatly enhances the carrying capacity of the antenna. The measured results show that the impedance bandwidth of the antenna is 75 MHz (0.303−0.378 GHz) and the axial ratio bandwidth is 50 MHz (0.32−0.37 GHz) in UHF band. In the L-band, the impedance bandwidth of the antenna is 550 MHz (1.18−1.73 GHz), and the axial ratio bandwidth of the antenna is 420 MHz (1.1−1.52 GHz). When the pressure reaches 390 kg/cm², the antenna can still work normally with a deformation of 3%. The measured results are basically consistent with the simulation results. The antenna has the characteristics of low profile, shared aperture, dual band and circular polarization, which provides a novel and practical antenna structure for vehicle wireless communication system, and can be embedded in the vehicle shell as part of the shell.