Particle Accelerators technology is evolving towards compactness and high efficiency. As a consequence, these devices are becoming suitable for several industrial and medical applications, such as linear accelerators for hadrontherapy treatments. In such scenarios, non-linear electromagnetic effects, such as field emission and surface breakdowns play a fundamental role in the limitation of the maximum gradient achievable. This work focuses on the study of these undesirable effects and new proposals to overcome this limitation. This seminar covers an overview of the field of accelerator physics, the conventional RF technology limitations and novel alternatives for the near future.