A Wideband Vivaldi Antenna with Modified Planar Marchand Balun for mmWave V2X Communications

This paper presents the design and character-ization of a wideband Vivaldi antenna for millimeter-wave (mmWave) vehicle-to-everything (V2X) communications. The antenna is designed to work at the frequency range of 24.25 GHz to 27.50 GHz (n258) tagged for fifth-generation (5G) mmWave. A planar Marchand balance-unbalance (balun), which was modified to suit a 50–Ω SMA connector avoiding bandwidth degradation, is used to feed the proposed antenna. The configuration is optimized to achieve an optimal design prior prototyping. Based on the optimization, a prototype of Vivaldi antenna is realized for experimental characterization. The result show that the realized antenna works well at the desired frequency range with the bandwidth achievement of 6.1 GHz from the frequency of 23.9 GHz to 30 GHz. In such frequency range, the gain is relatively constant, while the far-field radiation pattern indicates a directional nature.