| 摘要 |
PURPOSE:To make the beam performance of the transmitted pulse wave better and to improve the acquisition rate of data by giving a flare angle on the inner peripheral wall surface of an antenna so that the aperture end side may become large. CONSTITUTION:An inner wall 14 made of soft urethane is formed on the inner peripheral surface of a body 3. As to the inner wall 14, the lower end of the body 3, that means the part faced to the flange 9 of a reflector 8, has a prescribed thickness and the inner peripheral surface is formed in a taper shape so that the thickness may become 0 at the open end of the upper end and the open end side is enlarged. And 1,600Hz or 3,200Hz pulse wave is independently transmitted at intervals of 10 seconds in the sky from each transmitter-receivers 20, 21 and 22. The transmitted pulse wave is reflected by the scattering body 23 such as an inversion layer, etc., in the sky and also receives the frequency shift corresponding to the moving speed of the scattering body 23. The reflected wave is received by the transmitter-receivers 20, 21 and 22 so as to be analyzed in a controller 24. It is recognized that the occurrence of the side leak is apt to be smaller in a flare type based on the results of the experiment about the relation between the flare angle theta and a relative sound pressure level. |
