초록 ▼

A passive radar target comprises a sond lens (50) of substantially uniform dielectric constant, having a reflecting surface (51) integrally formed therewith, the lens being constructed of particulate material having a dielectric constant selected such that radar waves striking the surface of the sur

A passive radar target comprises a sond lens (50) of substantially uniform dielectric constant, having a reflecting surface (51) integrally formed therewith, the lens being constructed of particulate material having a dielectric constant selected such that radar waves striking the surface of the surface of the lens are focussed on the reflecting surface. In one form the particulate material comprise silica flour (91, 101) contained within a thin radar transparent polycarbonate shell. The shell is formed of two similar halves (102, 103) with a pressed aluminum reflective lining (92, 106) in one half. By making the lens axially symmetrical such that the forward and rearward surfaces have a radius of curvature that decreases with distance from the axis of symmetry (102, 103) the lens-reflector can be made to operate over a wide solid angle. In addition the paths of the reflected energy can be made slightly divergent since this has been found to optimise the reflected intensity and to provide the capability for detection of the target by a receiver spaced from the transmitter. Two such lens-reflectors back-to-back will provide substantially omnidirectional operation. In an alternative arrangement back-to-back concave reflecting surfaces (114, 115) are centrally located within a single spherical shell (117) filled with particular material (116). In some applications a particulate filler such as powdered slate is held by means of a polyurethane foam.

대표청구항 ▼

A passive radar target comprising: a lens comprised of a radar transparent shell; and a particulate material of substantially uniform dielectric constant filling said shell such that there are substantially no voids; and a reflecting surface integrally formed with said shell, said particulate materi

A passive radar target comprising: a lens comprised of a radar transparent shell; and a particulate material of substantially uniform dielectric constant filling said shell such that there are substantially no voids; and a reflecting surface integrally formed with said shell, said particulate material having a dielectric constant substantially equal to 3.4 such that radar waves striking the surface of the lens are focussed on the reflecting surface, said particulate material being finely powdered and compacted inside said shell.