Editing Transmission line (section)

===Planar lines===
{{main|Planar transmission line}}
Planar transmission lines are transmission lines with [[electrical conductor|conductors]], or in some cases dielectric strips, that are flat, ribbon-shaped lines.  They are used to interconnect components on [[printed circuit]]s and [[integrated circuit]]s working at microwave frequencies because the planar type fits in well with the manufacturing methods for these components. Several forms of planar transmission lines exist.

====Microstrip====
[[Image:Solec Kujawski longwave antenna feeder.jpg|thumb|right|A type of transmission line called a ''cage line'', used for high power, low frequency applications. It functions similarly to a large coaxial cable. This example is the antenna [[feed line]] for a [[longwave]] radio transmitter in [[Poland]], which operates at a frequency of 225&nbsp;kHz and a power of 1200&nbsp;kW.]]
{{Main|microstrip}}
A microstrip circuit uses a thin flat conductor which is [[Parallel (geometry)|parallel]] to a [[ground plane]]. Microstrip can be made by having a strip of copper on one side of a [[printed circuit board]] (PCB) or ceramic substrate while the other side is a continuous ground plane. The width of the strip, the thickness of the insulating layer (PCB or ceramic) and the [[dielectric constant]] of the insulating layer determine the characteristic impedance. Microstrip is an open structure whereas coaxial cable is a closed structure.

====Stripline====
{{main|Stripline}}
A stripline circuit uses a flat strip of metal which is sandwiched between two parallel ground planes. The insulating material of the substrate forms a dielectric. The width of the strip, the thickness of the substrate and the relative permittivity of the substrate determine the characteristic impedance of the strip which is a transmission line.

====Coplanar waveguide====
{{main|Coplanar waveguide}}
A coplanar waveguide consists of a center strip and two adjacent outer conductors, all three of them flat structures that are deposited onto the same insulating substrate and thus are located in the same plane ("coplanar"). The width of the center conductor, the distance between inner and outer conductors, and the relative permittivity of the substrate determine the characteristic impedance of the coplanar transmission line.