# Multi-Band Unmanned Aerial Vehicle Antenna for Integrated 5G and GNSS Connectivity
## 1 Introduction  
In today's rapidly changing world, the need for smooth connectivity and accurate navigation in vehicular networks is in high demand. There is an urgent need for technologies in vehicular networks to improve traffic management, increase road safety, and pave the way for autonomous driving as our cities and roads become more crowded. That is why the global navigation satellite system (GNSS) and the fifth generation technology (5G) have become revolutionary. The 5G cellular network technology is perfect for facilitating the vehicle-to-everything (V2X) communication because it promises unmatched speed, reduced latency, and extensive connectivity. At the same time, precise positioning and timing data are essential for fleet management, location-based services in cars, and navigation assistance, which are ensured by an in-built satellite navigation system. GNSS and 5G aim to enhance the efficiency, safety, and positioning for seamless communication across vehicular networks. In [1], a circularly polarized quad-band antenna was designed and fabricated to resonate in 5G n77, 5G n78, GNSS, and wireless fidelity (Wi-Fi) 6E bands. A single-patch L-shaped structure with a defective ground was developed on an FR4 substrate. It enhanced the gain of 4.56, 2.28, 4.26, and 4.30 dBi with circular polarization. In [2], a planar antenna of four bands was designed for the GNSS/wireless local area network (WLAN)/X-band applications. It was designed and fabricated on the FR4 material as a multi-band monopole antenna for vehicular rooftop applications. This single-portantenna operates in multiple bands, with peak gains of 5.7, 3.79, and 5.4. In [3], the antenna covering the 5G, sub-6 GHz, and LTE bands was designed on an FR4 substrate. The covered frequency achieved a gain of 3 dBi. In [4], multiple-input and multiple-output (MIMO) antennas needed for high-speed communication systems are discussed. The shift to MIMO antennas has advantages such as better channel capacity and the ability to concentrate radio frequencies on specific users. At the same time, difficulties faced while creating a compact MIMO antenna were also addressed. In [5], a wideband MIMO antenna with eight elements embedded on the FR4 material for the whole 5G band covering n78 and Wi-Fi at 5 GHz was designed and fabricated. Various performance analyses, such as the envelope correlation coefficient (ECC) and diversity gain, were calculated to validate the projected MIMO antenna's performance. In [6], a circularly polarized single-port antenna with a circular slot in the ground was designed and fabricated for wireless communication networks with dimensions of 50 \(\times\) 50 mm. By introducing semicircular loop feeding and adding a slit in the ground, multiple circular polarization resonant modes could be simulated simultaneously. In [7], a 4 \(\times\) 4 MIMO antenna for 5G networks was developed. This antenna operates across dual bands, explicitly targeting the 5G n78 and n79 frequencies. Within this framework, the two bands utilize the essential TM11 mode. Additionally, the higher-order mode is addressed through a combination of quasi-TM11 and TM0,1/2 modes. In [8], a four-port MIMO antenna was designed and fabricated for 5G n79 applications. The reversed L-shaped antenna with modifications at the ground plane and all four radiating elements were perpendicular to each other, such that a minimum isolation of 25 dB was achieved. This antenna works on a single band, with a peak gain of 2.8 dBi. In [9], a single antenna was designed and fabricated on FR4, that resonates at both 5G and GNSS bands. It was linearly polarized for 5G and right-hand circularly polarized for the GNSS, and it was suitable for automotive flat antenna modules. In [10], a four-element antenna array with right-hand circular polarization and a single feed was designed. A circular patch antenna was developed on Rogers TMM10i with a radius of 120 to achieve an RHCP.