| 摘要 |
A radar system for a helicopter having a mast (106) and a plurality of blade s (108) coupled to the mast by shaft portions of the blades (110) includes a transmitter (116) and a receiver (118) respectively transmitting and receiving a pulsed radar beam through a feed horn (120), a generator for generating the radar beam energy for transmission by the transmitter, a processor, a display, and a passive reflectarray (122) deposited on the underside (124) of at least one blade of the helicopter. The reflectarray is a preferably flat array of passive microstri p elements which can impart a phase to the radar beam. A typical microstrip element is a patch whose dimensions may be controlled, and the size of which determines the phase for the location within the array of that element. The reflectarray is provided with a pattern which is designed to scatter the radar beam in a desired shape and direction to produce uniform mapping of the terrain and sky mapping. The radar system of the invention provides a radar system utilizing a lightweigh t and inexpensive passive radar reflector for use on helicopters of all sizes, and achieves 360.degree. coverage.
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