Electromagnetic waves are waves that are formed due to vibrations between an electric field and a magnetic field. This book includes four chapters that present new applications and research on electromagnetic waves. Chapter One reviews the microwave absorption properties of CoFe2O4-based materials. Chapter Two examines strong resonance effects in ordered layered photonic structures for filtering, collimation, metrology and spectroscopy. Chapter Three describes an antenna array of upgraded quadruple sector emitters for wireless 4G networks. Lastly, Chapter Four explores the possibility of numerical solving scattering problems of electromagnetic waves by bodies with non-coordinate boundaries by reducing to infinite sets of linear algebraic equations relative to the coefficients of expansion of the unknown field in terms of eigen waves of coordinate domains in different coordinate systems.