Nanosized electronic systems are characterized by ballistic transport properties, which implies that the wave character of the electron plays a dominant role in such systems. We summarize some of the basic theoretical concepts involved, and point out various analogies between scalar electronic waves and electromagnetic vector waves. Those analogies should allow for a direct transfer of key technological concepts from optics or photonics to nanoelectronics. As an example, we discuss the concept of electronic metamaterials, and suggest a possible realization of nanometer sized electronic devices, based on novel low-dimensional carbon and boron nanomaterials.