# Horizontal Polarized DC Grounded Omnidirectional Antenna for UAV Ground Control Station
## 2 Antenna  
The structure of the suggested horizontally polarized omnidirectional antenna is shown in Figure 1. It must be shaped like a pole due to vehicle-mounting requirements. It is based on the coaxial line and is composed of inner and outer conductors. There are etched slots around the coaxial cylinder, and the internal and external coaxial cylinders are separated by air. The primary radiation is emitted via the slots (each slot is matched to a dipole with the magnetic current source), which are periodically positioned along the antenna's outer cylinder as depicted in Figure 1a. According to [PERSON]'s principle, the slots are complementary to the dipole antenna. The far field of the linear dipole [31], is found using:  
\[E_{\theta}=\left(j60I_{m}cos\ cos\ (klcos\theta)\ e^{-jkr}\right)/rsin\theta\]In the equation, \(\theta\) is the angle between the line direction and the dipole. This means the pattern function of the dipole is the same as the slot antenna. \[F_{\theta}=(cos\ cos\ (klcos\theta)\ -coskl)/sin\theta\]  
For idea half wavelength slot, 2l = \(\lambda/2\), and  
\[F_{\theta}=Cos(2\pi cos\theta)/sin\theta\]  
The pattern of the slot antenna is the same as the dipole with the same length, but their elevation plane (E-plane) and omnidirectional plane (H-plane) are exchanged according to the duality principle. Each slot aperture produces horizontally polarized radiation. Four apertures around the circumference complete the antenna, as illustrated in Figure 1a,b, and radiate in an omnidirectional pattern. The SMA connector smoothly converts the TEM modes from SMA to a large antenna assembly with a matching structure that is an optimized inner pin height, as given in Figure 1b. The diameter of the outer cylinder, the diameter of the feed pin that connects the inner cylinder to the outer part of the antenna, and the length of the slots are what primarily impact the performance of the antenna. The optimal specifications are listed in Table 1.  
At UAV GCSs, there are relaxed limitations with regard to size and weight compared to aerial platforms [32]. For military operations, the UAV operator at the GCS is located in a harmless, secured place while the desired information or strategic data from the battlefield is gathered remotely. For such applications, antennas must be capable of withstanding all terrain operational area requirements and should be able to function correctly under extreme weather scenarios. So the required antenna should be mechanically robust and sturdy without external supports as these supports would increase the antenna's size [4] and result in more drag, which might weaken the antenna's structure due to rigorous \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Value (mm)** \\ \hline Outer Cylinder Diameter A & 60 \\ Inner Cylinder Diameter B & 25 \\ Slot feed Pin Diameter P & 10 \\ Antenna Height H & 75 \\ Slot Length L & 65 \\ Slot Width W & 5 \\ SMA Pin Height T & 7.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Optimal parametric values of the antenna. Figure 1: The geometry of the horizontally polarized omnidirectional antenna: (**a**) 3D view, (**b**) cross-sectional view. terrain and weather conditions [4; 33]. Thus, it is crucial to use a compact, aerodynamic design. There is often a chance that an instance of peak instantaneous power (PIP) happens inside the printed circuit board- (PCB) based feed network. Such an event would easily damage the PCB [34], so the feed must be capable of bearing sudden PIP. The antenna would also be the primary source to channel electrostatic discharge (ESD) and lightning into the electronic systems. An ESD incident would place the functionality and safety of these systems at risk, while a lightning bolt would annihilate them. Keeping the antenna DC grounded is the most feasible and efficient strategy used in combat [35]. This antenna design would circumvent all the problems described above. The axis-symmetrical, all-metal rugged antenna is primarily constructed of brass and is DC-grounded.