Shark-Fin Antenna for Railway Communications in LTE-R, LTE, and Lower 5G Frequency Bands

This paper presents a design study of a shark-fin antenna for future railway communications. Three specific bands are considered here as LTE-R (700 MHz), LTE (2100 MHz), and Lower 5G band (3500 MHz). A 3-D metallic structure using the 3D printing technique has been designed and fabricated for the consideration of the required bands. The volume size of the antenna element is 163 x 61.9 x 10 mm(3). The multi-physical simulations in terms of the smooth air flow and lower drag coefficient are performed for analyzing the need of shark-fin radome cover. More than 70 MHz bandwidth was observed for the LTE-R band and also a wide band response from 1.4 GHz to 4.2 GHz was observed that cover the required bands well, i.e., the LTE, and Lower 5G band. The proposed shark-fin antenna results in the expected omnidirectional radiation pattern in the horizontal plane, with the radiation efficiency of 71.7%, 92.6%, and 96.4% in the railway environment for the LTE-R, LTE, and Lower 5G band frequency, respectively.