Implementation of a low Profile Risley Prism Using Additive Manufacturing

Satellite communication provides an important al- ternative to infrastructure in areas without internet access. Risley prisms are a good option for Low Earth Orbit satellite communication because of their beam steering properties. They are cheap to manufacture and more compact compared to the alternatives. In this report, an alternative design of a Risley prism is proposed, which suggests a decreased total height of the prism. Two matching layers is implemented to minimize reflections and obtain better directivity. A prototype of the prism is designed and implemented using additive manufacturing. Two ABS materials with relative permittivities εr1 = 8 and εr2 = 3 are used for the manufacturing. Simulations show promising results between 26 GHz and 28 GHz, with a directivity at approximately 25◦, a side lobe level of approximately −15 dB and an S11-parameter of −10 dB or lower. The directivity of the prism is measured to refract approximately 25◦ and the side lobe level is approximately 5 dB. Due to restrictions of the manufacturing and losses from the feeding antenna, the simulated results have a greater side lobe level than the measured ones. The prism is tested using a circularly polarized wave, when it is intended for a plane wave. This causes the measured results to differ from the simulated ones.