An omnidirectional low-profile dual-polarized UWB antenna for dual-functional applications in Internet of vehicles

In this paper, a snowflake-shaped low-profile ultra-wideband (UWB) antenna is reported for dual function multiplexing of the Passive Keyless Entry and Start (PKES) system and the Automated Valet Parking (AVP) system. This antenna demonstrates preferred properties of omnidirectional radiation patterns and dual polarization. Both horizontally polarized (HP) and vertically polarized (VP) elements cover the UWB band, ensuing reliable signal receiving/transmitting. The omnidirectional radiation patterns are obtained over the whole working frequency band, which is much preferred in uses of PKES and AVP. To realize omnidirectional patterns, the HP antenna comprises eight dual-antipodal Vivaldi antennas arranged in a circular array, connected by a 1-to-8 power divider. Corrugated edges and shorting pins are introduced to improve bandwidth. Meanwhile, the VP antenna is formed by two cross low-profile tapered monopolies, which also provide omnidirectional radiation over the whole UWB range. The proposed antenna boasts a compact size of only 96 × 96 × 7 mm, with a height of 0.07λmin (λmin represents the free-space wavelength at the minimum operating frequency). The realized bandwidth covers 3.06–10.62 GHz, which encompasses the UWB band and V2X band. The measured gain variation in different directions is less than 3 dB, confirming satisfactory omnidirectional radiation. Specifically, in the V2X band, the isolation is better than 25 dB. These advantageous properties render the antenna an ideal candidate for UWB applications of PKES and AVP in IoV.