Radar antenna for use in a miniature unmanned aerial vehicle

A miniature unmanned aerial vehicle (UAV) comprising:

• a plurality of propellers configured to provide upward thrust;
• a UAV body connected to the propellers;
• a radar system hanging from the UAV body, the radar system comprising a radar antenna comprising:
• a first printed circuit board having a first array of antenna elements situated at positions thereon, wherein the positions of antenna elements of the first array of antenna elements lie within a first predetermined distance range from a central axis perpendicular to the first printed circuit board, and wherein individual antenna elements of the first array of antenna elements each lie in differing directions from the central axis;
• a second printed circuit board, which is above and parallel to the first printed circuit board, wherein the second printed circuit board has a second array of antenna elements situated at positions therein, wherein the positions of antenna elements of the second array of antenna elements lie within a second predetermined distance range from the central axis, wherein individual antenna elements of the second array of antenna elements each lie in differing directions from the central axis, and wherein first element distances in the first predetermined distance range are smaller than second element distances in the second predetermined range;
• wherein the radar antenna further comprises:
• a first electrically conductive ring or plate that is:
• located between the first printed circuit board and the second printed circuit board, and
• configured to block lines of sight from the antenna elements of the first array to the antenna elements of the second array;
• and
• a second electrically conductive ring or plate;
• wherein the second printed circuit board lies between the second electrically conductive ring or plate and the first electrically conductive ring or plate, and
• wherein the second electrically conductive ring or plate extends radially outward beyond the first electrically conductive ring or plate;
• and a third electrically conductive ring or plate,
• wherein the first printed circuit board lies between the third electrically conductive ring or plate and the first electrically conductive ring or plate, and
• wherein the first electrically conductive ring or plate extends radially outward beyond the third electrically conductive ring or plate;
• transmission and reception electronics respectively coupled to the first array of antenna elements and the second array of antenna elements, or respectively coupled to the second array of antenna elements and the first array of antenna elements, the transmission electronics being configured to form an antenna beam having a beam direction;
• wherein the miniature UAV comprises an orientation sensor for measuring a rotation angle of the radar antenna around the central axis, and
• wherein the transmission electronics are configured to adapt the beam direction in response to angle changes sensed by the orientation sensor so as to compensate the beam direction for rotation of the radar antenna.