Communication device comprising a retroreflective structure
The disclosure relates to suppressing surface waves in a communication device for a wireless communication system. The communication device includes a dielectric layer extending along a plane between a chassis and a glass layer, an antenna element configured to emit a radio wave, and a retroreflective structure extending inside the dielectric layer and being located adjacent to the antenna element, and where the retroreflective structure is configured to reflect the radio wave in an angle non-parallel to the plane. The retroreflective structure hence prevents parasitic channeling of the antenna energy into surface waves in and behind the glass layer and directs the radiation into the desired direction.
1. A communication device for a wireless communication system, the communication device comprising:
a chassis;
a glass layer;
a dielectric layer extending along a plane between the chassis and the glass layer;
an antenna element configured to emit a radio wave; and
a retroreflective structure extending inside the dielectric layer and being located adjacent to the antenna element,
wherein the retroreflective structure is a conductive film that comprises capacitive elements and inductive elements forming a capacitive and inductive pattern, and
wherein the retroreflective structure is configured to reflect the radio wave in an angle non-parallel to the plane.
2. The communication device according to claim 1 , wherein the retroreflective structure has an inhomogeneous impedance along the extension inside the dielectric layer.
3. The communication device according to claim 1 , wherein the retroreflective structure is conductively or capacitively coupled to the antenna element.
4. The communication device according to claim 3 , wherein a first end of the retroreflective structure is conductively or capacitively coupled to the antenna element.
5. The communication device according to claim 1 , wherein the retroreflective structure is located within a range from the antenna element being less than half of the wavelength of the radio wave.
6. The communication device according to claim 1 , wherein the antenna element is arranged perpendicular to or parallel to the plane of the dielectric layer.
7. The communication device according to claim 1 , wherein the extension of the retroreflective structure inside the dielectric layer is less than half of the wavelength of the radio wave.
8. The communication device according to claim 1 , wherein the conductive film comprises a solid conductive film.
9. The communication device according to claim 1 , wherein a size of each capacitive element and each inductive element is less than quarter of the wavelength of the radio wave.
10. The communication device according to claim 1 , wherein the capacitive and inductive pattern is a non-repeating pattern.
11. The communication device according to claim 1 , wherein the capacitive and inductive pattern forms a grid pattern.
12. The communication device according to claim 1 , wherein the radio wave is a transverse magnetic polarized radio wave.
13. A method for producing a communication device for a wireless communication system, the method comprising:
obtaining a chassis and a glass layer;
obtaining a dielectric layer extending in a plane, the dielectric layer comprising a retroreflective structure extending inside the dielectric layer, wherein the retroreflective structure is configured to reflect a radio wave in an angle being non-parallel to the plane, and wherein the retroreflective structure is a conductive film that comprises capacitive elements and inductive elements forming a capacitive and inductive pattern;
arranging the dielectric layer between the chassis and the glass layer;
arranging an antenna element adjacent to the retroreflective structure; and
conductively or capacitively coupling the antenna element to the retroreflective structure.