10.1 Introduction10.2 Basics of Periodic Structures10.3 Filtering Characteristics of Passive Periodic Structures10.4 Natural Frequencies, Mode Shapes, and Response of Periodic Structures10.5 Active Periodic Structures10.6 Localization Characteristics of Passive and Active Aperiodic Structures10.7 Periodic Rod with Periodic Shunted Piezoelectric Patches10.8 Two‐Dimensional Active Periodic Structure10.9 Periodic Structures with Internal Resonances10.10 SummaryReferences10.A The Wavelet Transform