Two-dimensional horn imaging arrays (abstract)

A two-dimensional horn imaging array has been demonstrated at 242 and 93 GHz. In this configuration, a dipole is suspended in a pyramidal horn, fabricated by an anisotropic chemical etch technique, on a 1-µm silicon-oxynitride membrane. This approach leaves room for low-frequency lines and processing electronics. Pattern measurements on a 1.45-λ imaging array agree well with theory, show no sidelobes, and a 3-dB beamwidth of 35° and 46° for the E and H planes, respectively. Application areas include a superconducting tunnel-junction receiver for radio astronomy and imaging arrays for real-time electron density mapping in fusion plasmas. Support for this project was provided by DOE contract DE-FG03-86-ER-53225 (subcontracted from U.C.L.A.).