Compact 5 G mmWave vivaldi antenna for vehicular communication

As a key contribution, this article presents the first successful application of the newly developed Vivaldi Non-uniform Profile Antenna (VNSPA) theory to a Vivaldi Tapered Slot Antenna (VTSA) operating in the 26 GHz band (24.25–27.5 GHz). The proposed design achieves both compactness and simplicity while maintaining high performance. This antenna is a promising candidate for vehicular communication applications, aiming to enhance connectivity, road safety, security, and environmental system control. First, a VTSA with a small volume of 8.1 × 8.3 × 0.813 mm³ is designed, fabricated, and tested, providing S₁₁ value < -11.34 dB at 15.96–28.41 GHz and a maximum realized gain of 6 dBi. Second, a 33 % size reduction of its tapered slot profile (TSP) is obtained by applying the VNSPA theory, resulting in the Vivaldi Non-uniform Slot Antenna (VNSA). Based on this theory, two different non-uniform slot profiles (NSPs) are obtained for VNSA 1 and 2 with final 37 % and 32.55 % volume reduction, respectively, based on parametric studies. VNSA 1 and 2 provide S₁₁ values < -11.6 dB and < -14.3 dB at 16.71 to 27.68 GHz and 17.94 to 27.38 GHz with peak realized gains of 4.6 dBi and 5.15 dBi, respectively. Another key contribution of this research is the on-vehicle analysis of the proposed antenna's applicability for communication. This includes testing the antenna in various positions and demonstrating its capability to radiate in multiple directions, enabling effective communication with other vehicles, pedestrians, roadside units, and mobile networks. Another significant aspect of this research is the calculation of specific absorption rate (SAR), which addresses the effects of electromagnetic radiation on the driver, one back-seat passenger, and pedestrians. The Computer Simulation Technology (CST) software is used to carry out the simulation.