Attenuation controlling by means of a monolithic device

Claim 1

A monolithic device for controlling the transmission of RF energy comprising: a buffer layer having a predetermined conductivity, said buffer layer disposed on a semi-insulating substrate; doped regions selectively implanted in the buffer layer along two lateral lines, wherein the doped regions have a conductivity greater than the conductivity of the buffer layer; respective ground conductors disposed along each said lateral lines of doped regions to form an ohmic contact between each of said ground conductors and a respective one of said doped regions; and a signal conductor disposed directly on the buffer layer between said ground conductors to form a Schottky contact between said signal conductor and said buffer layer; a common ground plate, said semi-insulating substrate separating said buffer layer from said common ground plate, said semi-insulating substrate having via holes grounding said doped regions to said common ground plate; wherein said buffer layer is responsive to a source of DC potential connected between said signal and ground conductors for selectively attenuating the RF energy transmitted through said device.