Abstract: A new class of efficient vacuum electronic devices (VEDs) for THz wave generation and amplification are disclosed. The EM circuits of these VEDs are micro-fabricated from Si wafers with high precision. The original design of the EM circuits overcomes the main limitations of existing THz VEDs constructed from metal or metallized components, such as low fabrication precision, high signal losses, low tolerance to electric breakdown and low beam efficiency. The disclosed VEDs may have up to 50% beam efficiency in the THz band.

Abstract: A method and apparatus for an omnidirectional helically arrayed antenna are described. In accordance with at least one embodiment, a horizontally polarized omnidirectional helically arrayed antenna is provided. In accordance with at least one embodiment, an antenna comprises a helical array of coaxial transmission line radiating elements coupled to one another successively by phase changing couplings. In accordance with at least one embodiment, the antenna is configured to provide an omnidirectional radiation pattern and a polarization dominated by a magnetic field vector component parallel to an axis of the helical array and an electric field vector component perpendicular to the axis of the helical array. In accordance with at least one embodiment, an electrical length of each of the coaxial transmission line radiating elements is an odd integer multiple of a half wavelength in the coaxial medium with a pitch in the range of 0.35 wavelength to 0.50 wavelength.

Abstract: A miniaturized cylindrical `channeline` delay line comprises a plurality of concentrically stacked cylindrical elements, surfaces of which are configured to form helically contoured `channeline` transmission line. The nested stack includes a first, generally cylindrical conductive spool body element, for example a lightweight and electrically conductive cylinder or spool, having a longitudinal axis and an outer, generally cylindrical surface in which a helical groove is formed. Concentrically surrounding this interior spool are one or more additional, generally cylindrical hollow electrically conductive hollow cylinders of successively increasing diameters. These additional electrically conductive hollow cylinders are sized, so that respective ones of the cylinders may be concentrically stacked about the longitudinal axis of the interior spool. Like the interior spool, each surrounding cylinder has a helical groove formed in its outer cylindrical surface.

Abstract: A transmission delay line including a helical channel (2) formed in the surface of a cylinder (1), with a conductive sleeve (7) fitted to the cylinder to close the channel. A helical conductive member (4) is positioned within the channel (2) and spaced from the walls thereof by a dielectric material (5, 9).

Abstract: Helical slow-wave structure assemblies including a helical dielectric supporting member are disclosed along with methods for fabricating such assemblies. After the slow-wave structure helix is wound on a mandrel, a masking helix is coaxially wound about the slow-wave structure helix in the same sense as the slow-wave structure helix over the helical space between turns of the slow-wave structure helix and in overlapping relationship with portions of adjacent turns of the slow-wave structure helix. The supporting helix is formed by plasma spraying dielectric material into the helical space between turns of the masking helix. The dielectric material is ground to a predetermined radial dimension, and the mandrel and the masking helix are removed. By utilizing a masking helix of tapered width, a dielectric supporting helix of tapered width may be fabricated to provide a slow-wave structure assembly with a tapered phase velocity.