Abstract
This PhD thesis explores the design, fabrication and characterization of components for the development of a communication system and a deployment mechanism in a CubeSat for space application. The PhD research project focuses on developing these systems using fabricated printed electronics components utilizing additive manufacturing (AM) techniques such as 3D printing, screen printing, and water transfer printing. These devices, such as antennas and heaters, are particularly suited for CubeSats due to their lightweight nature and minimal space requirements. The thesis demonstrates the development of the antennas developed for internal and external communication in flat, curved and embedded configurations proving the ability to rapidly prototype components using AM techniques for custom requirements. This curved configuration offers significant benefits, including complex and conformable fabrication. The embedded configuration demonstrates space-saving advantages, as the components can be integrated within the walls of CubeSats, leaving the external surfaces available for other purposes. The first part of this research work, summarized in Chapter 5, focuses on the fabrication of ultra high frequency (UHF) dipole antenna. This antenna was designed and simulated using ANSYS HFSS software to operate at 865 MHz, aimed at providing internal telemetry using UHF frequency range (300 to 1000 MHz) within a CubeSat with a read range of a few meters. The UHF antenna fabrication utilized AM techniques: fused deposition modeling (FDM) for the substrate, and dispense printing and water transfer printing for flat and curved configurations, respectively. The curved configuration demonstrated the ability to produce non-flat, complex designs necessary for space applications. The measured resonant frequencies and return loss values of these antennas (-20 dB at 865 MHz and -7dB at 900 MHz for flat and curved configurations) were then compared with the simulated values (865 MHz at -25dB return loss) to evaluate performance. Dispense-printed antennas closely matched the simulations, while water-transferred antennas on flat PLA showed a frequency shift to 950 MHz and a reduced return loss of -10 dB due to distortion during transfer. Antennas on curved surfaces had an even lower return loss of -5 dB, indicating that substrate curvature affects the antenna’s radiation pattern and reduces return loss. The second part of this research, summarized in Chapter 6, focuses on the fabrication of microstrip patch antennas (MPAs). These antennas were designed to resonate at 2.4 GHz which falls under the s-band frequency range (2 to 4 GHz) and are primarily used to uplink and downlink information to and from CubeSats. Flat, curved, and embedded MPA configurations were fabricated using a combination of 2D and 3D additive manufacturing methods, including FDM, screen printing, water transfer printing, and ink injection into cavities. Embedding the MPA within a 3D-printed enclosure provides protection from environmental hazards and is beneficial for developing external applications, such as haptic interfaces. The MPAs were designed and simulated at 2.3 GHz, achieving an S11 value of -16.25 dB. The fabricated MPAs operated effectively within the 2.2 to 2.4 GHz range, with the flat MPA showing a higher S11 peak value compared to the curved and embedded versions. This study demonstrates that developing these AM MPAs in various configurations can enable the rapid creation of long-range antennas for innovative applications in aerospace and the Internet of Things (IoT) sectors. Additionally, the deployment system was developed using shape memory effect as summarized in Chapter 7. An autonomous hinge for the deployment of satellite radiators was developed. The hinge uses a shape memory alloy (SMA) which possesses the capability to move to specific shapes and orientations by memorizing the shapes based on the shape memory effect (SME). The developed hinge consists of Nickel-Titanium SME wires embedded within an ecoflex polymeric body. A printed heater that provides the temperature required (80°C for the first iteration of the hinge and 40°C for the second iteration of the hinge) by the SMA hinge for actuation is deposited on a Polyether ether ketone (PEEK) substrate using screen printing which is then placed on the ecoflex while it is still wet and is subsequently dried and solidified while being attached to the heater. The heater was powered to obtain the actuation temperature of 40◦C at which the hinge actuates from a flat orientation to a curved orientation with a 40◦ bending angle. Upon turning off the heater the hinge returns back to its flat orientation with a 10◦ residual angle in approximately 45 seconds. Finally, during a period abroad, as summarized in Chapter 8 a self-healing conductive and magnetic composite was developed using polyborosiloxane (PBS), carbon black, and neodymium (NdFeB). This composite was cut and reattached, demonstrating a full recovery of resistance (100 %). A 500-cycle bending test revealed that the composite exhibited consistent resistance variation when comparing its bent and stretched positions. Scanning electron microscopy confirmed the homogeneity of the mixture of components. The composite was magnetized using an electromagnet at 2T. Additionally, the composite was molded into soft robotic configurations, including rectangular, triangular, and gripper shapes, to utilize its actuating properties under the influence of a magnetic field. Bidirectional actuation was observed in all configurations, with 50 mT used to actuate and -50 mT to return the robots to their original states. The developed components, including antennas, were designed on a Polyether ether ketone (PEEK) substrate to demonstrate their compatibility with the harsh space environment. Hinges for deployment were also fabricated using materials suitable for space, such as Nickel-Titanium alloy for the shape memory wire and PEEK as the substrate for heaters. Silver ink was used to create the conductive parts in both applications, as metals are suitable for space. Additionally, a polyimide resin coating was applied to the hinge to ensure compatibility with the space environment.