## 4 Fractal Reflectarray Interference Analysis in Satellite Simulation Environment Scenario  
After the design and fabrication of the prototype of the proposed reflectarray, both the reflection and radiation characteristics of the design is then exported from CST to MATLAB to create a replica as a custom antenna. The Phi/Theta to Azimuth/Elevation conversion has been performed to align with the coordinate systems in MATLAB and CST Microwave Studio. The important satellite metrics can be summarised in relation to payload performance, space requirements, and data accuracy. Key metrics include gain, beamwidth, and size of the antenna mounted on the satellite. A chart summarising these key metrics is added in Table 4.  
As shown in Figure 9, after matching the 3D radiation pattern of the reflectarray on both platforms, the antenna is then evaluated for its performance in a real-time simulation environment. Initially, a satellite communication scenario is created in MATLAB with Low Earth Orbit (LEO) satellites and ground stations. Then, the designed custom antenna is mounted as the transmitter at LEO Satellites to evaluate receiver signal strengths at the desired ground station locations for a specified period. After that, the same custom antenna is used as a transmitter in a MEO satellite to evaluate the usefulness of the designed reflectarray in the case of interference with LEO satellites. The detailed flow of the real-time simulation environment testing process for the proposed reflectarray is presented in Figure 10. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Key Metrics** & **Role in Satellite Network** & **Criteria** \\ \hline \multirow{2}{*}{Payload Gain} & It is a measure of the antenna’s ability to focus and amplify signals over a long distance. & High gain for better communication \\ \hline \multirow{2}{*}{Payload Beamwidth} & Beamwidth is a measure for orienting the beam towards the desired direction, avoiding interference for a long distance. & Narrow beam for higher efficiency \\ \hline \multirow{2}{*}{Antenna Size} & Antenna size directly affects the overall size and cost of the satellite design and its launch into space. & Lower size, better space management \\ \hline \multirow{2}{*}{Bandwidth} & Payload bandwidth is the capacity of the communication system to transmit or receive data. & Higher bandwidth, big data handling capacity \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Key metrics for satellite communication with respect to the antenna. Figure 9: Three-dimensional radiation pattern matching between CST and MATLAB for the proposed reflectarray design. Initially, with the help of the Satellite Communication Toolbox in MATLAB, a satellite environment is created with a specified date and time. After that, satellites and ground stations are added as per their orbits around the Earth. In our case, the scenario is replicated from the Iridium NEXT satellite network, which contains 66 LEO satellites. The satellites are placed in six orbital planes with a difference of approximately 30-degree angles. In the next step, a ground station grid is created with specified latitude/longitude values from Google Earth to generate a coverage map and evaluate the received signal strength at the desired locations. The entire scenario, along with the Earth's orbit, is designed to operate at a 12 GHz frequency, as depicted in Figure 11.  
Figure 10: Workflow diagram for real-time simulation environment testing of the reflectarray in MATLAB. To incorporate the custom reflectarray antenna into this satellite scenario, it is assigned as the transmitter for the Low Earth Orbit (LEO) satellites. For the ground stations, the MATLAB inbuilt Gaussian antenna is taken into consideration. The 3D radiation pattern from the LEO satellite can be visualised in Figure 12, which clearly shows the radiation pattern of the proposed reflectarray design with a 30-degree phase shift from the main beam.