Antenna

1. An antenna having a circuit board which has at least one slot and a contact at the slot for feeding and/or picking up an electromagnetic signal,

wherein the slot is folded into itself and so forms a two-dimensional pattern on the circuit board;

wherein the slot has a plurality of arcs;

wherein the plurality of arcs comprise a middle arc having the largest height and side arcs having progressively smaller heights as a distance from the middle arc increases.

2. The antenna in accordance with claim 1 , wherein the antenna is a patch antenna for an RFID reading apparatus.

3. The antenna in accordance with claim 1 , further having a planar resonator in parallel with the circuit board.

4. The antenna in accordance with claim 1 , wherein the slot has enlarged end points.

5. The antenna in accordance with claim 1 , wherein the circuit board has two slots.

6. The antenna in accordance with claim 5 , wherein the two slots intersect one another.

7. The antenna in accordance with claim 5 , wherein the two slots each have a contact which is formed by a microstrip.

8. The antenna in accordance with claim 7 , wherein the microstrips form a power divider.

9. The antenna in accordance with claim 7 , wherein the microstrips are folded into themselves and so form a two-dimensional pattern on the circuit board.

10. The antenna in accordance with claim 7 , wherein the microstrips form the base shape of a rectangle which has a plurality of arcs at its side.

11. The antenna in accordance with claim 7 , wherein the microstrips form a dimple inwardly which is larger than the plurality of arcs at narrow sides of the rectangle.

12. An RFID reading apparatus having at least one antenna comprising a circuit board which has at least one slot and a contact at the slot for feeding and/or picking up an electromagnetic signal, with the slot being folded into itself and so forming a two-dimensional pattern on the circuit board; the antenna being suitable for transmitting RFID signals to an RFID transponder and/or for receiving RFID signals from an RFID transponder and the reading apparatus further having an evaluation unit for encoding RFID information into the RFID signals and/or for reading RFID information out of the RFID signals;

wherein the slot has a plurality of arcs;

wherein the plurality of arcs comprise a middle arc having the largest height and side arcs having progressively smaller heights as a distance from the middle arc increases.

13. The RFID reading apparatus in accordance with claim 12 for the stationary installation at one of a reading zone of a conveyor and of a reading portal for reading out at least one RFID transponder moved on the conveyor or through the reading portal.

14. A method of transmitting and/or receiving electromagnetic signals using an antenna having a circuit board which has at least one slot and a contact at the slot for feeding and/or picking up an electromagnetic signal, with the slot being folded into itself and so forming a two-dimensional pattern on the circuit board;

wherein the slot has a plurality of arcs;

wherein the plurality of arcs comprise a middle arc having the largest height and side arcs having progressively smaller heights as a distance from the middle arc increases.

15. The method in accordance with claim 14 , which is adapted of transmitting and/or receiving RFID signals.