Diffraction Radiation Antenna for 8-mm Waveband Radar Meant for Airfield Observation
High-resolution millimeter wave radars become an essential part of ground safety systems. Among them, radar systems for airfield traffic control are of special interest. The diffraction radiation antenna has been designed for it, using novel technology. The antenna consists of a ridged dielectric waveguide, diffraction grating, and focusing lens. The eigenwave of the ridged dielectric waveguide excites resonant oscillations in the elements of the diffraction grating.
A novel W-band radar for airport traffic monitoring: implementation, first operational results, perspectives
High resolution requirements for airport surface traffic monitoring with lightweight, small, all-weather sensors call for the use of a network of millimetre-wave radars to perform the surveillance function in the surface movement control and guidance system. In this paper a W-band radar employed as the basic sensor is described. Some results of recent and present field trials are reported.
Turbulent boundary layer wall‐pressure fluctuations downstream from an abrupt change in surface roughness
Spectra of wall‐pressure fluctuations beneath a turbulent boundary layer have been investigated immediately downstream from an abrupt change in surface roughness, from slightly rough to very rough. Over the measurable frequency band (400 Hz to 7 kHz), the spectra in the first 150 mm scale on wall variables. This indicates that the motions responsible for the pressure fluctuations measured in this region are very close to the wall. Farther downstream this scaling procedure breaks down. It is suggested that the initially thin internal layer behaves independently of the flow external to it until it has grown appreciably and only then interacts with the outer boundary layer. It was found that, for all frequencies measured, the dimensional spectral level decreases initially then rises to a maximum at 250 mm from the roughness change before decreasing once more. The position of the maximum is close to where the internal layer ceases to have a distinct edge.