In order to explore and exploit the frequency range from 30 GHz up to THz, new types of transmission lines and semiconductor architectures are needed. Conventional microwave technologies that are commonly used below 30 GHz become either too lossy or are too expensive to manufacture, and technologies used in the optical regime are not usable either. The intermediate frequency band is therefore often referred to as the THz gap, indicating the lack of commercialize-able technologies there.Professor Kildal has invented a fundamentally new regime of transmission line, referred to as gap waveguides. The basis is newly discovered local waves appearing in the gap between two conducting surfaces, controlled by a texture in one or both of the surfaces. The gap waveguide has been verified below 20 GHz, but it will be more advantageous in the THz gap. The texture will for THz applications be of submillimeter or micrometer scale, realizable by micromachining or etching. Also, there is no need for a dielectric substrate, and there is no need for conductive contact between the two surfaces. Therefore, such gap waveguides and circuits for the THz gap can be manufactured with low cost.The vision is that the topology of this new regime of gap waveguides will facilitate integration of semiconductor devices, and may lay the foundation for new architectures of transistors and other integrated circuits, being located inside the gap encapsulated by the conductive surfaces themselves. In order to reach this vision new and efficient numerical electromagnetic methods and modeling tools need to be developed, taking advantage of the particular gap waveguide geometry, and being able to connect to or replace the charge transport models for the transistors in the doped semiconductors themselves.The gap waveguide technology can get a tremendous impact on exploring higher frequencies in radio astronomy, communications, and imaging for medical as well as security applications.