Reflectarray and a millimetre wave radar

A reflectarray comprising an array of patch elements (10-13;

• 89, 91), each patch element being designed to shift a phase of an incident polarized electromagnetic wave by a predetermined phase angle α,
• and each patch element having a cut ring shape (28) formed of a conductive ring (30) with at least one crossing gap (32), the conductive ring having an outer diameter ro and an inner diameter ri and each crossing gap having a respective width h,
• wherein diameters ro, ri and width h are adjusted so that a phase shift β defined by the following relations is different from zero
• φ(Eox)=φ(Eix)+α (1)
• φ(Eoy)=φ(Eiy)+α+β (2)
• where:
• Eix and Eiy are the orthogonal components of the incident polarized electromagnetic wave collinear with directions ux and uy, respectively,
• Eox, and Eoy are the orthogonal components of the reflected polarized electromagnetic wave collinear with directions ux and uy, respectively,
• φ(Eox) and φ(Eoy) are the phases of the orthogonal components Eox and Eoy, respectively, and
• φ(Eix) and φ(Eiy) are the phases of the orthogonal components Eix and Eiy respectively.