Miniaturization of Microstrip Antennas for Applications in Cubesats
The objective of this work was to develop a compact microstrip antenna for use in CubeSats, a type of miniaturized satellite mainly used for space exploration and research, used in low earth orbit. The small size of satellites presents a great challenge to the project. One of the main components being a satellite board, an antenna determines the performance of all wireless systems, including: telemetry, tracking, and control (TT&C); downlink of high-speed data; navigation; communications between satellites; radars; and sensors. For the TT&C function, expandable wire antennas are often employed in V-UHF. However, the use of the release mechanism of these antennas can fail and compromise a mission. Therefore, a compact microstrip antenna is desirable. The work presents a literature review covering some concepts about the CubeSat pattern, the fundamentals of antenna theory, such as the main techniques for the miniaturization of antennas, the fundamentals of electrically small antennas, and the main works already developed on the subject. Further investigation was carried out on Wheeler’s method to measure the radiation efficiency of compact antennas, this method is applied to measure the radio efficiency of the built prototype. The work methodology consists of designing, simulating, building, and characterizing a microstrip antenna operating at two frequencies (401,6 MHz and 435,0 MHz) based on the fundamentals of the literature review. These frequencies were chosen to meet the requirements of most CubeSats in use, but in particular, they meet two of the frequencies planned for CONASAT, a project of the Northeast Regional Center (CRN) of the National Institute for Space Research (INPE), located in Natal, in partnership with the Federal University of Rio Grande do Norte (UFRN). The contribution of this work lies in the ability of the developed prototype to operate at two frequencies with a single power supply point, thus reducing the weight, complexity, and risk of failures in the CubeSats communication systems.