The aim of this thesis is to introduce a new concept of distributed radiating and oscillating device by investigating and manipulating some dispersive properties of particular periodic structures based on planar technology. Floquet-Bloch modes describe the propagation of electromagnetic waves in periodic transmission lines. Two-port periodic guiding structures allow the occurrence of regular band edge (RBE), that is a fundamental class of exceptional point of degeneracy (EPD). Under these special dispersion conditions, both the two system eigenvectors and eigenvalues coalesce. This represents a standing wave where energy is not flowing through the periodic circuit. A description of the wide range of applications in which dispersive degeneracy conditions have crucial importance is presented.