Design and Implementation of Vivaldi Antenna with Modified Marchand Balun for V2X Communications

This paper presents the design and implementation of Vivaldi antenna for vehicle-to-everything (V2X) communications. The proposed antenna, which aims to work at the frequency of 3.5 GHz, is fed by a Marchand balance-unbalance (balun) unit to provide an interface to a 50-Ω SMA connector. In order to avoid bandwidth degradation, such a balun is terminated with an open stub. Parametric simulations using a full-wave electromagnetic (EM) simulator are performed to obtain the optimal dimensions of antenna. To verify the design experimentally, a prototype of Vivaldi antenna is implemented and measured. The result of characterization indicates that the proposed Vivaldi antenna performs well across a 380 MHz frequency bandwidth from the frequency of 3.40 GHz to 3.78 GHz. In such a bandwidth, the antenna gain is relatively constant, and the far-field radiation pattern shows a directional nature. Therefore, the proposed Vivaldi antenna is suitable for V2X communications.