Thick substrate mode transmitting antennas for monolithic millimeter wave development

A semiconductor-type superstrate is essential for monolithic fabrication that includes active devices. It can be electrically thick, and therefore mechanically rugged, without preventing the use of transmission line type models in the design of oscillators for transmitter type active antennas. The power output of these oscillators can be easily coupled into the superstrate, power combined therein and radiated via an end face of the dielectric slab to create a completely new aperture-type active antenna that may be developed as a monolithic millimeter wave component. A low dielectric constant layer may be used between the ground plane and the metal strip when accurate thin spacings of a few hundred microns are required at frequencies approaching 100 GHz. The development of high electron mobility transistors (HEMTs) has created prospects for more efficient millimeter wave oscillators than those that use IMPATT or Gunn diodes. The design shown incorporates one or more transistor oscillators monolithically fabricated on the surface of a thick dielectric slab that is enclosed by a metallic housing to form a partially filled resonator that radiates through an aperture in one of its side wall.