An X-Band Array Antenna for Forward Looking Radar in Collision Avoidance Systems of Locomotives

In this work, an X-band array antenna is proposed for a radar system aimed to detect obstacles in front of a locomotive. Such a radar system can assist the train driver in forward collision avoidance in scenarios with compromised frontal visibility. The antenna is designed on an ARLON25N substrate with a thickness of 1.6 mm. According to the specification, the antenna has a maximum gain larger than 16 dBi and an operating frequency from 9.4 to 9.7 GHz. The array elements are simple patch elements which form a 8×8 2-dimensional array with an appropriate spacing between the elements in order to minimize the side lobes. The feeding structure is studied including end- and center-feed in order to satisfy the required specifications. The input of the feed is matched to 50 Ohm to minimize the return loss. The X-band array antenna will be installed inside the locomotive right behind the frontal wind shield to protect the radar module from the weather conditions outside the locomotive. The proposed system will contribute to enhanced safety of railway transportation as well as road users at railway crossings without barriers.