Directional coupler

1. Directional coupler having at least one coupling line piece which is coupled to a coaxial inner conductor of coaxial line pieces and, for this purpose, the coupling line piece is provided on or adjacent to a coupler substrate which is arranged on a resting or mounting section of an outer conductor of the coaxial line piece in a region of a cutout in the outer conductor, and the coupling line piece is in this way held in a space between the inner conductor and the outer conductor, comprising:

an attenuation circuit adjacent and connected to each of the two coupling line ends on the coupler substrate, or an attenuation circuit connected to one coupling line end with a terminating resistor being connected to the other coupling line end on the coupler substrate,

an electrical level evaluation circuit device provided on the coupler substrate, and

an interface device for connection of possibly unshielded cables provided on the coupler substrate, or possibly unshielded cables are connected to the level evaluation circuit device or connected downstream from the level evaluation circuit device on the coupler substrate, via which the RF signals which are obtained via the coupling line piece can be passed on in the form of analog AF signals.

2. Directional coupler according to claim 1 , characterized in that the attenuation circuit is in the form of a Π circuit.

3. Directional coupler according to claim 1 , characterized in that the attenuation circuit is in the form of a T circuit.

4. Directional coupler according to claim 1 , characterized in that a level detector is provided on the coupler substrate, preferably adjacent to or downstream from each of the two coupling line ends.

5. Directional coupler according to claim 1 , characterized in that a memory module which is preferably in the form of an EEPROM memory module is also provided on the coupler substrate and is used to store the transfer function of at least one and preferably both coupling arms, and of electronic evaluation.

6. Directional coupler according to claim 1 , characterized in that the coupler substrate ( 19 ′) has a multilayer structure.

7. Directional coupler according to claim 1 , characterized in that the coupler substrate has a central section in the region of the exposed cutout in the outer conductor in the coaxial line piece, and in that an additional extension section is provided at least in a lateral direction from this central section, for holding further electrical or electronic components.

8. Directional coupler according to claim 1 , characterized in that the coupling line piece is in the form of a stripline, a wire clip or a wired component, preferably in the form of a resistor.

9. Directional coupler according to claim 1 , characterized in that the electrical level evaluation circuit device and interface device are fitted or provided on the upper face of the coupler substrate and/or on the lower face of the coupler substrate.

10. Directional coupler according to claim 1 , characterized in that elements for temperature compensation are furthermore also provided on the coupler substrate.

11. Directional coupler according to claim 1 , characterized in that, in addition to assemblies for detecting absolute level information, the directional coupler also has assemblies for detecting difference values for a level and phase between the two coupling arms.

12. Directional coupler according to claim 1 , characterized in that components which determine a frequency, in particular bandpass filters or bandstop filters, are provided in at least one coupling arm, preferably in both coupling arms, in particular for suppressing interference frequencies.

13. Directional coupler according to claim 1 , characterized in that the directional coupler preferably also has a microprocessor on the coupler substrate.