Progress In Two-Dimensional Horn Imaging Arrays

Two-dimensional horn-antenna imaging arrays have been fabricated for 93 GHz. In this configuration, a dipole antenna is suspended in a pyramidal horn on a 1-μm silicon oxynitride memb This approach leaves room for low-frequency lines and processing electronics. Pattern measurements on single elements agree well with theory, exhibiting 3-dB beamwidths of 54° and 62° for the E and H-planes respectively. Horn aperture efficiencies of 44 ± 4% (including mismatch and resistive losses) have been measured. Possible applications include imaging arrays for remote sensing, plasma diagnostics and radiometry, and superconducting tunnel-junction receivers for radio astronomy.