Note that N-port networks in [[RF.Spice]] have schematic symbols with 2N pins. Each pair of pins represents a port. In a similar way, the generic T-line has two ports and four pins. The pins are marked with plus and minus signs. For example, in the figure above, the pins P1+ and P1- together form Port 1. Normally, the negative pins are grounded, and the positive pins are connected to the other parts of the circuit.
{{Note | Proper grounding of the [[Transmission Lines|[[Transmission Lines|[[Transmission Lines|[[Transmission Lines|[[Transmission Lines|[[Transmission Lines|[[Transmission Lines|transmission lines]]]]]]]]]]]]]] device is critical for a successful simulation.}}
[[File:tline2.png|thumb|350px| The schematic symbols of the Generic Open Stub (left) and Generic Short Stub (right) devices.]]
* Twisted-Pair Line
The physical transmission line types are characterized by their physical dimensions and material properties. The following table shows the [[parameters]] of each transmission line type:
[[Image:Info_icon.png|40px]] Click here to see a [[List of Physical Transmission Line Types]].
{| class="wikitable"
|-
! Line Type !! Model Name !! [[Parameters]] !! Image !! Schematic Symbol
|-
| Microstrip Line || microstrip-line || len: line segment length in mm <br /> w: microstrip width in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity <br /> sigma: microstrip conductivity in S/m <br /> tand: substrate dielectric loss tangent <br /> t: metallization thickness in mm || [[File:microstrip.png]] || [[File:microstrip1.png|120px]]
|-
| Coupled Microstrips || coupled-microstrips || len: line segment length in mm <br /> w: strip width in mm <br /> s: microstrip spacing in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity || [[File:coupled_microstrips.png]] || [[File:coupled_microstrips1.png|120px]]
|-
| Covered Microstrip Line || microstrip-covered || len: line segment length in mm <br /> w: microstrip width in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity <br /> hc: cover height in mm || [[File:microstrip_cover.png]] || [[File:CoveredMS1.png|120px]]
|-
| Suspended Microstrip Line || microstrip-suspended || len: line segment length in mm <br /> w: microstrip width in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity <br /> b: height of substrate above ground in mm || [[File:SUSPMS.png]] || [[File:SuspMS1.png|120px]]
|-
| Inverted Microstrip Line || microstrip-inverted || len: line segment length in mm <br /> w: microstrip width in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity <br /> b: microstrip height above ground in mm || [[File:INVMS.png]] || [[File:InvMS1.png|120px]]
|-
| Coplanar Strips (CPS) Line || cps-line || len: line segment length in mm <br /> w: strip width in mm <br /> s: strip spacing in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity || [[File:CPS.png]] || [[File:CPS1.png|120px]]
|-
| Stripline || stripline || len: line segment length in mm <br /> w: strip width in mm <br /> b: parallel plate spacing in mm <br /> er: substrate relative permittivity <br /> sigma: strip conductivity in S/m <br /> tand: substrate dielectric loss tangent <br /> t: strip thickness in mm || [[File:stripline.png]] || [[File:stripline1.png|120px]]
|-
| Coupled Striplines || coupled-striplines || len: line segment length in mm <br /> w: strip width in mm <br /> s: strip spacing in mm <br /> b: parallel plate spacing in mm <br /> er: substrate relative permittivity || [[File:coupled_striplines.png]] || [[File:coupled_striplines1.png|120px]]
|-
| Off-Center Stripline || coupled-striplines || len: line segment length in mm <br /> w: strip width in mm <br /> s: offset from centerline in mm <br /> t: strip thickness in mm <br /> b: parallel plate spacing in mm <br /> er: substrate relative permittivity || [[File:OffCenter.png]] || [[File:OffStrp1.png|120px]]
|-
| Coplanar Waveguide Line || cpw-line || len: line segment length in mm <br /> w: slot width in mm <br /> s: center strip width in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity || [[File:cpw.png]] || [[File:cpw1.png|120px]]
|-
| Conductor-Backed CPW Line || cbcpw-line || len: line segment length in mm <br /> w: slot width in mm <br /> s: center strip width in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity || [[File:cbcpw.png]] || [[File:cbcpw1.png|120px]]
|-
| Covered CPW Line || cpw-covered || len: line segment length in mm <br /> w: slot width in mm <br /> s: center strip width in mm <br /> h: substrate thickness in mm <br /> hc: cover height in mm <br /> er: substrate relative permittivity || [[File:cpw_cover.png]] || [[File:CovCPW1.png|120px]]
|-
| Covered Conductor-Backed CPW Line || cbcpw-covered || len: line segment length in mm <br /> w: slot width in mm <br /> s: center strip width in mm <br /> h: substrate thickness in mm <br /> hc: cover height in mm <br /> er: substrate relative permittivity || [[File:cbcpw_cover.png]] || [[File:CovCBCPW1.png|120px]]
|-
| Finite-Ground CPW Line || fgcpw-line || len: line segment length in mm <br /> w: slot width in mm <br /> s: center strip width in mm <br /> g: ground strip width <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity || [[File:fgcpw.png]] || [[File:fgcpw1.png|120px]]
|-
| CPW Line with a Superstrate || cpw-super || len: line segment length in mm <br /> w: slot width in mm <br /> s: center strip width in mm <br /> g: ground strip width in mm <br /> h: substrate thickness in mm <br /> er: substrate relative permittivity <br /> hs: superstrate height in mm <br /> ers: superstrate relative permittivity || [[File:SuperCPW.png]] || [[File:SuperCPW1.png|120px]]
|-
| Double-Layer CPW Line || cpw-doublelayer || len: line segment length in mm <br /> w: slot width in mm <br /> s: center strip width in mm <br /> h1: lower substrate layer thickness in mm <br /> er1: lower substrate layer relative permittivity <br /> h2: upper substrate layer thickness in mm <br /> er2: upper substrate layer relative permittivity || [[File:DoubleCPW.png]] || [[File:DoubleCPW1.png|120px]]
|-
| Coaxial Line || coaxial-line || len: line segment length in mm <br /> r_in: inner conductor radius in mm <br /> r_out: outer conductor radius in mm <br /> er: dielectric core relative permittivity <br /> sigma: metal conductivity in S/m <br /> tand: dielectric core loss tangent || [[File:coax.png]] || [[File:coax1.png|120px]]
|-
| Twin-Lead Line || twin-lead || len: line segment length in mm <br /> r: wire radius in mm <br /> s: wire spacing in mm <br /> er: dielectric medium relative permittivity <br /> sigma: wire conductivity in S/m <br /> tand: dielectric medium loss tangent || [[File:twin.png]] || [[File:twin1.png|120px]]
|-
| Twisted-Pair Line || twisted-pair || len: line segment length in mm <br /> r: wire radius in mm <br /> s: wire spacing in mm <br /> T: number of twists per length in 1/m <br /> erc: dielectric cover relative permittivity <br /> erm: dielectric medium relative permittivity <br /> sigma: wire conductivity in S/m <br /> tand: dielectric cover loss tangent || [[File:twisted.png]] || [[File:twisted1.png|120px]]
|-
|}
[[File:tline5.png|thumb|450px| The schematic symbols of the some Physical Transmission Line Discontinuity devices. (Top Row) microstrip components: right-angled bend, mitered bend, tee and cross junctions, (Bottom Row) CPW components: open end, short end, gap and step junction.]]