Design, analysis and demonstration of a hybrid analog/digital retro-directive antenna system for satellite communications

Retro-directive antenna systems are a promising solution to the challenges found in satellite communications. This thesis encompasses the complete development cycle of an innovative hybrid retro-directive antenna system architecture: analytic description, simulations in continuous and discrete time, implementation, and validation by measurements. Thus, it allows the reader to comprehend all aspects of the presented retro-directive antenna system. The thesis is organized as follows: After an introduction to the concept of retro-directivity, a comprehensive overview of past and current retro-directive antenna systems is presented. Taking the requirements of modern satellite communication systems into account, a suitable analog/digital hybrid system architecture is proposed. Its distinctive features are full-duplex operation, usage of array gain on transmit and receive, and array squint correction. System theoretic investigations founded on phase transfer functions are conducted to predict the system performance. The obtained results are validated by continuous time simulations. Finally, the system is implemented using analog and digital hardware. The resulting demonstrator is used to proof the retro-directive capability of the proposed system concept by monostatic and bistatic measurements in an anechoic chamber.