Presented by: Gustavo Blando In this introductory talk, I’ll start by reviewing resonances commonly found in SI topologies in an intuitive way. In particular, I’ll concentrate on half wave resonances. At a very fundamental level I’ll discuss: What resonances are? How do they develop? And how to identify them with dips/peaks in the frequency domain S-parameters? The study of half wave resonances will set the baseline to understand periodical discontinuities. The theory will be presented first and then, several examples and practical mitigation strategies will be shown for both half wave resonances and periodical discontinuities.