# Multi-Band Unmanned Aerial Vehicle Antenna for Integrated 5G and GNSS Connectivity
## 1 Introduction
This design is tailored for applications in the upper L-band of the GNSS and has a defective ground structure and MT-30 microwave absorber to achieve high isolation. In [11], an antenna system for integrating 5G and the right-hand circularly polarized GNSS L1/L5 band was proposed; this can be used on a vehicle's roof inside low-profile housing. In [12], an antenna pair for mobile terminals was designed and fabricated on the FR4 material with a MIMO configuration for the 5G n77/n78/n79 5G bands; it satisfies all MIMO parameters and is capable of good data transmission. However, it operates in only one band, with an enhanced gain of 4.2-8.2 dBi. In [13], a MIMO multi-band antenna was designed and fabricated for 5G, WI-FI-6, and WLAN devices using an FR4 substrate. This MIMO multi-band antenna was designed by duplicating a single-element antenna and placing it orthogonally to the first element. The multi-port, multi-band antenna improves the gain to 2.2, 3.4, and 3.41 dBi. In [14], an eight-element MIMO antenna for ultra-wideband applications was designed. It also achieved good MIMO parameters, making it suitable for portable ultra-wideband applications. In [15], a jug-shaped coplanar waveguide for ultra-wideband MIMO applications was designed and fabricated on FR4 with a size of 60 \(\times\) 60 mm. Here, the MIMO port components were positioned orthogonally to each other for self-decoupling [16]. This MIMO antenna was designed for future 5G devices; it achieves a gain of 3.4 dBi, has an efficiency of over 65% over the entire bandwidth and a maximum value of 92.7% at the resonant frequency. An E-shaped microstrip patch antenna array was designed, and electronic beam steering with high directivity for space applications was proposed [17]. Further, increasing the number of radiating elements improved the antenna's gain value to 7.01 dBi. In [18], a two-element multi-band MIMO antenna was developed and manufactured to cater to Ka-band satellite communication, millimeter-wave technology, 5G networks, and forthcoming 6G wireless communication systems. In [19], the MIMO design was compared to dual-band, ultra-wideband, and circularly polarized antennas. The antenna performance was analyzed based on the envelope correlation coefficient (ECC), efficiency, isolation techniques, gain, and channel capacity loss (CCL). Finally, in [20], a coplanar waveguide with a circularly polarized rectangular slot antenna was designed and fabricated for the GNSS in vehicular applications. It was designed according to the direction in which windshields are tilted, with a glass substrate. This work developed an inverted T-shaped patch with a defective ground for dual-port, dual-band, dual-polarized antennas with maximum gain. The comparison analysis of the proposed approach with the literature is included in Table 1 for ease of understanding. The positioning of a dual-port antenna on a drone for outdoor 5G and GNSS connectivity is displayed in Figure 1. The main contributions of this paper are as follows:  
* A single-port inverted T-shaped antenna with defected ground was designed to resonate in the GNSS and 5G bands with circular polarization. * Appropriate orthogonal placement of a dual-port MIMO antenna to reduce the electromagnetic interaction among the antenna structures. * A single square ring-shaped frequency selective surface (FSS) was designed for broadband coverage. * Investigation of an FSS integrated dual-port MIMO antenna for outdoor 5G and GNSS applications.