DESIGN AND IMPLEMENTATION OF CIRCULAR PATCH ANTENNA ARRAY FOR UPLINK AND DOWNLINK IN THE STARLINK LOW EARTH ORBIT SATELLITE COMMUNICATION SYSTEM

• Main Author: Arifin, Hafidz
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/82261
• Institution: Institut Teknologi Bandung

LEO (Low Earth Orbit} satellites are systems with antenna components orbiting the Earth at altitudes between 500 and 1200 km. LEO satellites are used because they offer significant benefits in providing communication services. Due to their low orbit altitude, these satellite systems deliver communication services with minimal latency. Currently, Starlink is the company with a large consteJJation of LEO sateJJites. Starlink has launched an extensive constellation of LEO satellites to provide broad internet access world wide. The LEO satellites used by Starlink operate in the Ku-band frequency range, which spans 12-18 GHz. The Starlink satellite system features two transmission directions: downlink and uplink, utilizing different frequency bands. The 10.7 - 12.7 GHz frequency band is used for downlink transmissions, while the 14 - 14.5 GHz band is used for upHnk transmissions. One of the advantages of using the Ku-band frequency for LEO satellites is the small size of the antenna system, which can reach LEO satellites with significant bandwidth and gain. For example, the Starlink ground antenna measures 30x50 cm and contains 1,400 elements. A microstrip antenna consists of a very thin metal sheet atop a substrate. This type of antenna supports various feeding methods, configurations, and radiating patch shapes. The flexibility in design, compact size, simple fabrica tion, and ease of integration are parameters that make microstrip antennas advantageous. One feeding method to achieve a wide frequency bandwidth is the aperture coupled feed microstrip antenna. This method allows bandwidth tuning by varying the slot on the ground and the gap between the transmission line and the radiating patch. This document covers research on a circular patch microstrip antenna with aperture coupled feed As previously mentioned, this antenna was chosen for its advantages, such as high efficiency and wide bandwidth. The design process invol ves selecting optimal antenna parameters, such as patch dimens ions, element spacing, and substrate type. The designed antenna js then fabricated and tested to ensure its performance meets expectations. The prototype antenna tested consists of 32 elements, while Starlink '.s ideal antenna configuration has 1,400 elements. Thus, the comparison between the fabricated antenna and the ideal antenna is 1:44. However, the prototype antenna achieved operating frequencies of 10.5 - 12.8 GHz and 14 - 14.5 GHz. These frequency ranges indicate that the prototype antenna operates identically to Starlink's LEO sateJJite system. The radiation pattern produced by the antenna shows good characteristics, with a main focus on the desired dkection (dkectional antenna). The prototype antenna has a gain of 12.9 dBi at 12 GHz and a gain of 14.46 at 14.26 GHz, while the desired gain is 37.8 dm for the 1.400-element configuration. Based on these results, it can be conduded that the prototype antenna can be further developed to achieve a gain of 37..8 dBi by adding more elements and considering the Sllbstrate type used. However, as a prototype antenna, these results are reasonable compared to Starlink's ideal antenna.