Structure for reducing scattering of electromagnetic waves

1. A structure that is invisible to certain frequency bands, comprising:

a transmission line network comprised of a connected mesh of transmission lines; and

a transition layer at a boundary of the structure;

wherein the transmission line network has been matched with a surrounding space.

2. The structure according to claim 1 , characterized in that the structure minimizes scattering when it is designed as following:

the period of the transmission line network is smaller than a wavelength of the incident radiation;

the sites of the structure are chosen so that the scattering to the desired direction is minimized (the phase shift between the free space and the structure is minimized); and

the transition layer has been dimensioned so that the incident (or incoming) power is transmitted in the transmission line network.

3. The structure according to claim 1 , characterized in that the transmission line network is either one-, two- or three-dimensional.

4. The structure according to claim 1 , characterized in that the transmission lines of the transmission line network have been connected with two-dimensional plane or with three-dimensional space.

5. The structure according to claim 1 , characterized in that there is a transition device on the boundary of the structure which is an antenna arrangement between surrounding space and transmission line network.

6. The structure according to claim 1 , characterized in that the invisible structure has been designed for a constant periodicity of transmission line network, advantageously 8 mm and that the diameter of the invisible cylinder is fixed, advantageously 12 cm and the structure is designed to work in frequencies near 6 GHz.

7. The structure according to claim 1 , further comprising:

supporting structures inside the transmission line network.

8. The structure according to claim 7 , characterized in that the supporting structures are cylinders placed inside the transmission line network.

9. The structure according to claim 8 , characterized in that the supporting cylinders are electrically conductive.

10. An assembly that is invisible to certain frequency bands, comprising:

a structure configured so that a radiation incident upon the structure passes freely through the material;

a transmission line network formed as a mesh of interconnected transmission lines;

supporting structures inside the transmission line network; and

a transition device at a boundary of the transmission line network and a surrounding space,

the transition device being in connection with the transmission line network, and

the transmission lines of the transmission line network configured to propagate a wave from the incident radiation freely inside the structure.

11. The structure according to claim 10 ,

wherein a period of the transmission line network is smaller than a wavelength of the radiation incident upon the structure, the radiation originating from a source at a distance and direction from the structure, and

wherein a thickness of the structure is such that a scattering of the incident radiation is minimized.

12. The structure according to claim 10 , wherein the supporting structures are wires placed between elements of the transmission line network.

13. The structure according to claim 10 , wherein the transmission line network comprises transmission lines arranged in a two-dimensional mesh.

14. The structure according to claim 13 , wherein the transmission line network comprises transmission lines arranged as a stack of said two-dimensional meshes connected with each other for form a three-dimensional mesh.

15. The structure according to claim 10 , wherein the transition device is a plurality of antennas arranged along an outermost boundary portion of the transmission line network.

16. The structure according to claim 15 , wherein the antennas of the transition device are metal strips with varying widths.