This thesis investigates potential technologies to increase the integration density of CubeSats. Observations of the CubeSat market and missions are recorded in order to derive design criteria for high performance single unit CubeSats. A promising approach to increased integration density is relocation of the components of multiple satellite subsystems to form a highly integrated, multi-functional solar panel. Eligible components are usually allocated to the communication system, the electric power system, or the attitude determination and control system. In a joint research project, development, optimization, and miniaturization of those components in order to form a highly integrated, multi-functional solar panel is investigated. The author first summarizes the development work of the project partners for a picosatellite solar antenna and puts it into relation to the overall solar panel design. Advantage of using solar antennas over simple patch antennas is the reduced loss of solar cell area, and hence available electric power, that is usually accompanied by the usage of higher frequency bands for broadband payload data transmission. Magnetic attitude actuators are the backbone of CubeSat attitude control. In order to increase their performance and lower their resource consumption, numerical optimization of the commonly used three coil types is investigated by the author. This leads to the formulation of a novel optimization approach, which is better suited to real-world considerations for magnetic actuator design. Results from the application of the optimization procedure show potential for every coil type. The state of the art of a novel type of attitude control actuators, so-called fluid-dynamic actuators which are based on angular momentum exchange, is advanced by the author by introducing miniaturized 3D-printed conduits for single unit CubeSat applications. Following development and functional verification, actuators are compared to existing reaction wheel systems, which shows their superiority for agile attitude maneuvers and integration with the satellite bus. Further investigation exploits additive manufacturing technologies to create redundancy concepts using four actuators with three-dimensional conduits.Finally, development, optimization, and miniaturization of subsystem components is brought together in the design, assembly, and test of a highly integrated, multi-functional solar panel. Analysis of a single unit CubeSat design that applies different configurations of the multi-functional solar panel shows the potential for more than 50% payload mass and payload volume. This brings integration density of single unit CubeSats to a level similar to that of the larger triple unit form factors currently employed for the New Space mega-constellations.