Design and Implementation of Multibeam Multi- Panel Antenna Array for Cellular mm-Wave 5G Vehicle-To-Everything (V2X) Communications Amar D. Chaudhari 1 , Abhishek Kumar 2 , Sourav Ghosh 3 , Soumava Mukherjee 4 1,2 Bharti School of Telecommunication Technology and Management, Indian Institute of Technology Delhi, New Delhi 110016, India 3,4 Department of Electrical Engineering, Indian Institute of Technology Jodhpur, Jodhpur 342037, India 1 chaudhari.amar27@gmail.com, 2 abbhishek2011@gmail.com, 3 ghosh.3@iitj.ac.in, 4 soumava@iitj.ac.in Abstract—In this paper, a low-profile substrate integrated waveguide H-plane sectoral horn antenna with wide bandwidth and high gain is designed. An extended dielectric along with the extended bottom broadwall is utilized to improve the impedance matching between horn aperture and free space. To feed the antenna, a simple coaxial probe is used. The simulated results show that the horn antenna achieves a wide bandwidth of 20.6% (24.16 - 29.72 GHz) for |S11| < -10 dB with a compact size of only 18.3 mm × 20.6 mm. The extended bottom broadwall enhances the gain and acts as a reflector providing an inclined main beam. The antenna has a peak gain of 9.2 dBi with an inclination angle between 50-60º. These features of the designed horn antenna are suitable for implementing a multibeam antenna array with full azimuth coverage for application in cellular mm-Wave 5G vehicle-to-everything communications. By placing eight horn antenna panels in a sequentially rotated arrangement, a multibeam antenna array is implemented with a compact footprint. The antenna array has shown good inclined beam switching and omnidirectional capabilities over wide impedance bandwidth obtained with low profile and volume. Keywords—Coaxial feed, H-plane horn antenna, low-profile, multibeam antenna, multiple-input-multiple-output (MIMO), substrate-integrated waveguide (SIW), vehicular communication, wide bandwidth. I. INTRODUCTION Over the past years, vehicle-to-everything (V2X) communications have attracted many research interests due to their advantages of improved safety, reduced traffic congestion, autonomous driving, platooning, etc. It facilitates an intelligent transport system by incorporating various types of communication like vehicle-to-vehicle (V2V), vehicle-to- infrastructure (V2I), vehicle-to-pedestrians (V2P), vehicle- to-network (V2N), as illustrated in Fig. 1 [1]. 3GPP defined cellular connectivity as the backbone connection for V2X applications and started developing new standards based on the 5G NR in Release 16 and Release 17 [2, 3]. In recent literature, vehicular antennas/arrays, including tri-polarized [4], beam switching [5], multibeam [6], and phased array [7], have been reported to cover 5G sub-6 GHz and mm-Wave bands. The mm-Wave wireless systems enable wide band, high data rate, low latency and high- reliability communication. However, waves at the mm-Wave band undergo larger free-space path loss. Therefore, V2X communications antennas must have high gain, low profile, and the ability to cover the full 360º azimuth range. Multibeam antenna arrays are a promising candidate for the mm-Wave band as it provides many directive beams for wide angular coverage [6, 8-10]. In [6], a shared aperture multibeam multiband antenna array has been proposed based on the Vivaldi antenna and dipole to operate at sub-6 GHz and mm-Wave frequency bands. The 360º azimuth coverage is achieved by replicating four such antennas on a circular shape and four in a cross-shaped substrate to radiate eight beams. The overall structure is two-dimensional and has a total volume of 120 mm × 120 mm × 30 mm. In [8], full azimuth coverage is obtained by twelve radiating beams. Here, an array of SIW horn antennas operating from 27.5 to 38 GHz has been designed over a single-layer circular-shaped substrate having a total volume of 90.6 mm × 90.6 mm × 1.524 mm. In [9] and [10], two high gain multibeam antennas are designed by placing phased arrays/antennas in a circular array to cover the full azimuth range. All aforementioned multibeam antenna arrays are either implemented over a common substrate or with sub-arrays, making them large in size and bulky. The substrate integrated waveguide (SIW) horn antenna is one of the most popular antennas because of its low profile, easy integration with planar circuits, and low cost. However, the difference in dielectric between horn antenna substrate and free space at the aperture reduces bandwidth and low gain. Many efforts have been made to improve impedance matching, such as extending dielectric substrate [11], extended graded dielectric substrate [12, 13], extended dielectric with periodic structures [14, 15], grading horn aperture substrate [16], and loading horn aperture with air- filled cavity [17] or with rows of vias [18]. However, all the reported SIW horn antennas either have limited bandwidth, gain or high realization complexity. These limits their This work was supported by the Indian Institute of Technology Delhi, under project RP04156G, funded by Ministry of Electronics and Information Technology (MeitY), India. Fig. 1. Different types of communications in 5G V2X scenario. 2022 IEEE Microwaves, Antennas, and Propagation Conference (MAPCON) 978-1-6654-5203-8/22/$31.00 ©2022 IEEE 410 2022 IEEE Microwaves, Antennas, and Propagation Conference (MAPCON) | 978-1-6654-5203-8/22/$31.00 ©2022 IEEE | DOI: 10.1109/MAPCON56011.2022.10047071 Authorized licensed use limited to: Indian Institute of Technology - Jodhpur. Downloaded on December 22,2023 at 17:53:19 UTC from IEEE Xplore. Restrictions apply.