Device for transferring signals from a metal housing

1. A device for enabling wireless communication with a field device, comprising:

a transmitting and receiving unit disposed in a field device housing and embodied to generate and to receive electromagnetic waves from an opening in the field device housing, which is metallic at least in part;

a primary antenna disposed in the housing embodied to decouple the generated electromagnetic waves of the transmitting and receiving unit and to couple and transfer the received electromagnetic waves to the transmitting and receiving unit;

a first secondary antenna embodied to receive the generated electromagnetic waves decoupled from the primary antenna, the first secondary antenna disposed within the housing in the housing opening; and

a second secondary antenna embodied to receive electromagnetic waves transferred from outside the housing, the second secondary antenna disposed outside the housing in the housing opening,

wherein the first secondary antenna is joined to the second secondary antenna at a reflection point between the first and second secondary antennas, such that an impedance jump occurs between the first and second secondary antennas.

2. The device of claim 1 , further comprising a cable gland disposed within the housing opening.

3. The device of claim 2 , wherein the cable gland is a PG cable gland.

4. The device of claim 2 , wherein the cable gland is filled at least partially with a dielectric filling material.

5. The device of claim 4 , wherein the dielectric filling material is a dielectric sealing compound.

6. The device of claim 4 , wherein the first and second secondary antennas are held inside the cable gland by the filling material.

7. The device of claim 1 , wherein the reflection point is embodied as an abrupt change in a diameter of the first secondary antenna to a diameter of the second secondary antenna.

8. The device of claim 1 , wherein the reflection point is embodied as a shared antenna base of the first and second secondary antennas.

9. The device of claim 8 , wherein the shared antenna base has a plate-shaped form, and wherein the shared antenna base is disposed such that a first plane defined by the shared antenna base and a second plane defined by a wall of the housing at the housing opening coincide.

10. The device of claim 1 , wherein the first secondary antenna, the second secondary antenna, or both secondary antennas have a length that corresponds to a whole-number multiple of one quarter of at least one specific wavelength.

11. The device of claim 1 , wherein the first secondary antenna, the second secondary antenna, or both secondary antennas are rounded at an open end opposite the reflection point.

12. A device for enabling wireless communication with a field device, comprising:

a transmitting and receiving unit disposed within a field device housing;

a primary antenna disposed within the field device housing and embodied to couple electromagnetic waves with the transmitting and receiving unit; and

a secondary antenna including a first part and a second part, the first part disposed in the field device housing and the second part disposed outside the field device housing via an opening in the field device housing, the first part and the second part joined to each other at a reflection point at which there is an impedance change between the first part of the secondary antenna and the second part of the secondary antenna,

wherein the first part of the secondary antenna is embodied to transfer electromagnetic waves between the primary antenna and the second part of the secondary antenna, and

wherein the second part of the secondary antenna is embodied to transfer electromagnetic waves between the first part of the secondary antenna and a device external to the field device housing.