High-gain step-profiled integrated diagonal horn-antennas

Dipole-excited integrated horn antennas are limited by their large flare angle of 70°, which is inherent in the anisotropic etching process of ?100? silicon wafers. The large flare angles does not allow for integrated horns with gain higher than 13 dB and for 10-dB beamwidths less than 90°. A step-profiled horn is proposed which reduces the effective flare angle of the horn and allows gains in the region 17 dB to 20 dB to be achieved. The symmetry of the horn's radiation pattern is enhanced by positioning the exciting dipole along the diagonal of the horn cavity. A specific design example is shown with a gain of 18.4 dB and a 10-dB beamwidth of 37° in the E, H and 45° planes. The coupling efficiency of this horn to a Gaussian beam is calculated to be 83%. An equivalent smooth envelope-horn was built at 12.1 GHz and the measured patterns agree well with theory. The integrated step-profiled horn is well suited for millimeter-wave and terahertz focal plane imaging arrays requiring a large number of elements