Integration of Antennas and Solar cells for Low Power Wireless Systems

This thesis reports on design methods for enhanced integration of low-profile antennas for short-range wireless communications with solar voltaic systems. The need to transform to more sustainable energy sources arises from the excessive production of harmful carbon emissions from fossil fuels. The Internet of Things and the proliferation of battery powered devices makes energy harvesting from the environment more desirable in order to reduce dependency on the power grid and running costs. While photovoltaic powering is opportune due to immense levels of available solar power, the separate area requirements for the antenna and the photovoltaic surfaces presents an opportunity to significantly minimize the unit volume and to enable portable deployment. The focus is on issues of integrating antennas and transmission lines above crystalline silicon solar cells, in particular, the relative orientations are complicated by a-symmetric lattice of the solar cell. A solution to minimise orientation sensitivity was provided and utilised to successfully isolate a microstrip transmission line from the solar lattice, thereby allowing four antenna configurations to be demonstrated. Further work on crystalline solar cells demonstrated their use alongside circularly polarised antennas for aerial vehicles. Wireless energy harvesting over a wide frequency range was demonstrated with an a-Si solar Vivaldi antenna. A dye-sensitised solar dipole antenna was developed for low power indoor applications. The approaches established the engineering capacity to reduce the device size and weight through integration of the radio and the solar cell technologies. In addition, the use of different solar cell technologies demonstrated the importance of selecting the cell type most suited to the intended application