A new monolithic millimeter-wave two-dimensional horn imaging array is presented. In this configuration, a dipole is suspended in an etched pyramidal cavity on a 1-µm silicon-oxynitride membrane. This approach allows ample space for low-frequency interconnections, while still maintaining efficient diffraction-limited imaging. The fabrication procedure of the horn array and the deposition parameters of the membrane layer are presented in detail. The array is analysed rigorously, by approximating the horn antenna by a structure of multiple rectangular waveguide sections. Pattern measurements at 93 GHz and 242 GHz agree well with the theory. The results show thathorn antennas with an opening between 1.0λ and 1.5λ have high aperture efficiencies and would match well appropriate imaging systems.Also, a new wideband log-periodic antennas is integrated on a thin membrane and tuned by a back plane reflector. The antenna patterns are measured at 167 GHz, 370 GHz and 700 GHz, and the effect of the back-plane reflector is investigated at 370 GHz.
