Hello Forum,
I always thought, naively, that a circuit powered by a DC or RF generator with a transmission line connecting it to a load, needed two conductors to close the circuit. One conductor being the signal conductor while the other the return conductor.
Is the return conductor always necessary in a circuit? If so, why?
The voltage is a concept that needs to be applied at two points (conductors).
Does current in a circuit always need to form a closed circuit? Why?
With two conductors we can then have two currents, equal and opposite. But what do we do with a transmission line made of only one conductor? Both equal and opposite currents exist on conductor: zero net current...maybe?
If we connect a AC battery terminal to a single wire, that wire becomes an antenna.
Has anyone heard about single-wre transmission lines (Goubau line)?
How does a single-conductor transmission line like the Goubau line work?
Is the longitudinal current inside it equal to zero? If it is zero, why so?
How about the voltage on this line?
All I know the field propagates as a surface wave wrapped outside the single metal wire. I tried to find simple conceptual explanation but not luck so far.
(Microwave waveguide are composed of only one conductor too. But the field (modes) are trapped inside the guide and propagate by reflecting off the guide walls. There is then propagation without any conductors, free space propagation (free space can be viewed as an infinite spherical waveguide).
Thanks
antennaboy
I always thought, naively, that a circuit powered by a DC or RF generator with a transmission line connecting it to a load, needed two conductors to close the circuit. One conductor being the signal conductor while the other the return conductor.
Is the return conductor always necessary in a circuit? If so, why?
The voltage is a concept that needs to be applied at two points (conductors).
Does current in a circuit always need to form a closed circuit? Why?
With two conductors we can then have two currents, equal and opposite. But what do we do with a transmission line made of only one conductor? Both equal and opposite currents exist on conductor: zero net current...maybe?
If we connect a AC battery terminal to a single wire, that wire becomes an antenna.
Has anyone heard about single-wre transmission lines (Goubau line)?
How does a single-conductor transmission line like the Goubau line work?
Is the longitudinal current inside it equal to zero? If it is zero, why so?
How about the voltage on this line?
All I know the field propagates as a surface wave wrapped outside the single metal wire. I tried to find simple conceptual explanation but not luck so far.
(Microwave waveguide are composed of only one conductor too. But the field (modes) are trapped inside the guide and propagate by reflecting off the guide walls. There is then propagation without any conductors, free space propagation (free space can be viewed as an infinite spherical waveguide).
Thanks
antennaboy