Extending the pitch of the hydroacoustic parametric antenna array thanks to axial interlaced shift of elements in half the pitch
Abstract
Extending the pitch of the hydroacoustic parametric antenna array thanks to axial interlaced shift of elements in half the pitch
Incoming article date: 06.12.2020This article deals with the parametric hydrophone antenna arrays the elements of which are connected in parallel on one coordinate (in the columns). The mathematical models had been developed which were derived from the formula of the directional characteristic of a right-angled flat radiator embedded into the absolutely hard baffle. A level of overshoots of the directional characteristic (as related to a principal maximum) amounts no more than 0.15; a coefficient of decreasing overshoots of the directional characteristics because of shifting lines is approximately equal to two 2 for the array (8 x 8 or 16 x 16) with a pitch equal to wave length, with shifting lines to half the array pitch, a gap between the elements is 0.1 of the array pitch and a direction of beams is from 5 to 18 degrees on both sides with respect to the normal to an antenna plane. Without the gap between the elements at the abovementioned conditions the overshoots and the coefficient of their decreasing will no more than 0.1 and approximately 2.4 respectively. Thanks to extending the antenna array pitch a number of antenna elements is being reduced, and consequently, a number of the power amplifiers will be reduced as well. The simulation results are presented including computed two-dimensional directional characteristics of the antennae. The overshoot dependences upon beam direction and antenna array element dimension are also shown.
Keywords: hydroacoustis parametric antenna array, narrow sector of scanning, parametric, antenna, nonlinear, element, array, array pitch, directional characteristic, overshoot, overshoot level, increasing of array pitch