Glazing unit with frequency selective coating and method

1. A glazing unit comprising:

a glass panel which is low in reflectance for RF radiation,

a coating system which is high in reflectance for RF radiation disposed on the said glass panel, and

at least one frequencies selective decoated portion of the coating system extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Z; having a width, DW, measured along the longitudinal axis, X, and a length, DL, measured along the vertical axis, Z, comprising a first decoated element comprising a plurality of unit cells forming a regular grid of n rows by in columns unit cells, where m and n are positive integers higher than 1 (n>1 and m>1), and a plurality of second decoated elements wherein at least one second decoated element is placed in a unit cell of the first decoated element and wherein no second decoated element is in contact with the first decoated element,

wherein at least one unit cell of the first decoated element has no second decoated element.

2. The glazing unit according to claim 1 , wherein several unit cells of a row and/or a column of the first decoated element have no second decoated element.

3. The glazing unit according to claim 2 , wherein several unit cells of several row and/or several columns of the first decoated element have no second decoated element.

4. The glazing unit according to claim 1 , wherein at least one frequencies selective decoated portion comprises a plurality of third decoated elements having no contact with the first decoated element and second decoated element.

5. The glazing unit according to claim 4 , wherein at least one segment of the second and/or the third decoated elements is substantially parallel to one side of the unit cells of the first decoated element.

6. The glazing unit according to claim 1 , wherein at least one of the plurality of third decoated elements is placed in an unit cell of the first decoated element without a second decoated element.

7. The glazing unit according to claim 1 , wherein the at least one unit cell of the first decoated element having no second decoated element is free of any decoated element.

8. The glazing unit according to claim 1 , wherein the second and/or the third decoated elements comprise:

a. a first segment AB wherein a point B is a free termination,

b. a second segment CD wherein a point D is a free termination,

c. an intersection point E between the first segment AB and the second segment CD forming sub-segments AE, EB, CE and ED wherein a length, EB , of the sub-segment EB is less than a length, AE , of the sub-segment AE and higher than 0 (0< EB < AE ), and wherein a length, ED , of the sub-segment ED is less than a length, CE , of the sub-segment CE and higher than 0 (0< ED < CE ).

9. The glazing unit according to claim 8 , the second and/or the third decoated elements further comprising:

more than or equal to one additional segment and

interactions points between segments, and

wherein each segment has one interaction point with another segment and wherein each segment has at most two intersection points with two different other segments to form a closed shape.

10. The glazing unit according to claim 9 , wherein the second and/or the third decoated elements comprise two additional segments:

a third segment FG wherein the point F is a free termination and an intersection point H between the third segment FG and the second segment CD forming sub-segments FH, HG, CH, HE and ED wherein a length, HG , of the sub-segment HG is less than a length, FH , of the sub-segment FH and higher than 0 (0< HG < FH ) and

a fourth segment IJ wherein a point I is a free termination and an intersection point K between the fourth segment IJ and the third segment FG forming sub-segments IK, KJ, FK, KH and HG wherein a length, KJ , of the sub-segment KJ is less than a length, IK , of the sub-segment IK and higher than 0 (0< KJ < IK )

forming central sub-segments and lateral sub-segments.

11. The glazing unit according to claim 10 , wherein the second and/or the third decoated element comprises a fourth segment IJ wherein a point I is a free termination, an intersection point K between the fourth segment IJ and the third segment FG forming sub-segments IK, KJ, FK, KH and HG wherein the length, KJ , of the sub-segment KJ is less than the length, IK , of the sub-segment IK and higher than 0 (0< KJ < IK ) and an intersection point L between the fourth segment IJ and the first segment AB forming sub-segments AL, LE, EB, IL, LK and KJ wherein the length, KJ , of the sub-segment KJ is less than a length, KL LK , of the sub-segment K and higher than 0 (0< KJ < LK ).

12. The glazing unit according to claim 11 , wherein a sum of the lengths of sub-segments between intersection points is equal to nλ wherein n is a positive integer greater than 0 ( LE + EH + HK + KL =nλ wherein n is a positive integer greater than 0.

13. The glazing unit according to claim 1 , wherein each unit cell of the first decoated element is a regular square with sides in X and Z axis to form a regular squared grid decoated element.

14. The glazing unit according to claim 1 , wherein an emissivity of the coating system is greater than 0.01 and less than 0.04.

15. The glazing unit according to claim 1 , wherein the at least one frequencies selective decoated portion is at most 3% of a total coated area of the coating system.