In accordance with one or more embodiments, a dielectric coupler includes a neck portion configured to receive a first electromagnetic wave from a hollow waveguide. A flared portion is configured to generate, responsive to the first electromagnetic wave, a second electromagnetic wave along a surface of a transmission medium, wherein the flared portion at least partially surrounds the transmission medium, wherein the second electromagnetic wave propagates along the surface of the transmission medium without requiring an electrical return path. A tapered portion is configured to interface the neck portion to the flared portion.

A directional coupler includes a multilayer body, a conductor (31), and a conductor (32). The conductor (31) is a conductor that is arranged in an insulating layer (21) of the multilayer body and that extends in a certain shape. The conductor (32) is arranged on a side of an insulating layer (22) of the multilayer body opposite the insulating layer (21). The conductor (32) runs parallel to the conductor (31) and is electromagnetically coupled to the conductor (31). The conductor (32) has a winding shape with one or more rounds, and has a conductor portion (321) and a conductor portion (325) that are arranged adjacent to each other with a spacing in a direction orthogonal to a running parallel direction. In plan view of the multilayer body, the conductor (31) is arranged between the conductor portion (321) and the conductor portion (325).

Aspects of the subject disclosure may include, a system having an absorber and a coupling device. The absorber includes absorbent material that absorbs radiation. The coupling device is positioned in and surrounded by the absorber. The coupling device facilitates transmitting or receiving of an electromagnetic wave along a transmission medium, where the electromagnetic wave propagates along the transmission medium without requiring an electrical return path. Other embodiments are disclosed.

Electromagnetic coupler systems including built-in frequency detection, and modules and devices including such. One example of an electromagnetic coupler system includes an electromagnetic coupler having an input port, an output port, a coupled port, and an isolation port, the electromagnetic coupler including a main line extending between the input port and the output port, and a coupled line extending between the coupled port and the isolation port, the electromagnetic coupler being configured to produce a coupled signal at the coupled port responsive to receiving an input signal at the input port. An adjustable termination impedance is connected to the isolation port. A frequency detector is connected to the adjustable termination impedance and to the coupled port, and configured to detect a frequency of the coupled signal and provide an impedance control signal to tune the adjustable termination impedance based on the frequency of the coupled signal.

The planar waveguide converter is a silica-glass, bi-directional planar waveguide converter, providing conversion from an input from a single-mode waveguide to an output for a three or four-mode waveguide. Conversion takes place through an intermediate stage of a pair of two-mode waveguides. In the initial stage, the input from the single-mode waveguide passes through a V-shaped, graded-index mode slicer, where it is converted into a pair of two-mode signals. In the intermediate stage, each of the two-mode signals is received by a corresponding diamond or quadrilateral-shaped phase shifter. The output of each phase shifter is transmitted to an M-shaped, graded-index mode combiner, which outputs either a three or four-mode signal.

Aspects of the subject disclosure may include, for example, a coupling module that includes a waveguide that guides a first electromagnetic wave conveying data from a transmitting device. A dielectric coupler receives the first electromagnetic wave from the waveguide to form a second electromagnetic wave, and that guides the second electromagnetic wave along the dielectric coupler adjacent to a transmission medium, and wherein the dielectric coupler has a length that supports a cancellation of at least one cancelled wave mode from a coupling of the second electromagnetic wave to the transmission medium.

An annual directional coupler having at least three taps, which are each arranged relative to one another around routes having a wavelength difference of of a wave guide wavelength, includes in particular at least two branch lines, wherein a first branch line has at least three taps and wherein the at least second branch line does not have any taps and is supplemented by an additional route corresponding to the wave guide wavelength.

Aspects of the subject disclosure may include, a system having an absorber and a coupling device. The absorber includes absorbent material that absorbs radiation. The coupling device is positioned in and surrounded by the absorber. The coupling device facilitates transmitting or receiving of an electromagnetic wave along a transmission medium, where the electromagnetic wave propagates along the transmission medium without requiring an electrical return path. Other embodiments are disclosed.

Electromagnetic coupler systems including built-in frequency detection, and modules and devices including such. One example of an electromagnetic coupler system include an electromagnetic coupler having an input port, an output port, a coupled port, and an isolation port, the electromagnetic coupler including a main line extending between the input port and the output port, and a coupled line extending between the coupled port and the isolation port, the electromagnetic coupler being configured to produce a coupled signal at the coupled port responsive to receiving an input signal at the input port. An adjustable termination impedance is connected to the isolation port. A frequency detector is connected to the adjustable termination impedance and to the coupled port, and configured to detect a frequency of the coupled signal and provide an impedance control signal to tune the adjustable termination impedance based on the frequency of the coupled signal.

Aspects of the subject disclosure may include, for example, a coupling module that includes a waveguide that guides a first electromagnetic wave conveying data from a transmitting device. A dielectric coupler receives the first electromagnetic wave from the waveguide to form a second electromagnetic wave, and that guides the second electromagnetic wave along the dielectric coupler adjacent to a transmission medium, and wherein the dielectric coupler has a length that supports a cancellation of at least one cancelled wave mode from a coupling of the second electromagnetic wave to the transmission medium.