### RF Designer - Components (Physical Transmission Lines)

Posted:

**Wed Jan 07, 2015 5:57 am**Physical Transmission Line Elements

TLINP - Physical Transmission Line

Model for a physical and lossy transmission line. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

TLPOC - Physical Open Circuited Transmission Line

Model for a physical and lossy open circuited transmission line. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

TLPSC - Physical Short Circuited Transmission Line

Model for a physical and lossy short circuited transmission line. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

TLINP4 - Physical 4 Node Transmission Line

Model for a physical and lossy transmission line with the ground terminals left open and available as ports in the schematic. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

CLINP - Physical Coupled Transmission Line

Model for a pair of lossy symmetric coupled transmission lines. Length is specified as a physical length(L). Coupling is determined by the even and odd mode impedances (Zoe and Zoo), effective dielectrics (EeffE and EeffO), and attenuation per unit length(AE and AO) over the specified physical length (L).

Given a desired coupling C in decibels, Zoe = Zo * ((1 + k) / (1 - k)) where k = power(10.0, -C/20.0). Zoo can the be found by solving Zoo = Zo * ((1 - k) / (1 + k))

Example: Find Zoe and Zoo for a 10 dB coupler in a 50 ohm system.

First calculate k as k = power(10.0, -10/20) = 0.316

Zoe is found as Zoe = Zo * ((1 + .316) / (1 - .316)) = 96.2 ohms

Zoo is found as Zoo = Zo * ((1 - .316) / (1 + .316)) = 26 ohms

TLINP - Physical Transmission Line

Name | Description | Units | Default Value |

Z | Impedance | Resistance | 50 ohms |

L | Physical length | Dimensions | 1000 mil |

εeff | Effective dielectric constant | Unitless | 1.0 |

A | Attenuation per unit length | decibels | 0 dB/mil |

F0 | Frequency for attenuation factor | Frequency | 1000 MHz |

Model for a physical and lossy transmission line. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

TLPOC - Physical Open Circuited Transmission Line

Name | Description | Units | Default Value |

Z | Impedance | Resistance | 50 ohms |

L | Physical length | Dimensions | 1000 mil |

εeff | Effective dielectric constant | Unitless | 1.0 |

A | Attenuation per unit length | decibels | 0 dB/mil |

F0 | Frequency for attenuation factor | Frequency | 1000 MHz |

Model for a physical and lossy open circuited transmission line. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

TLPSC - Physical Short Circuited Transmission Line

Name | Description | Units | Default Value |

Z | Impedance | Resistance | 50 ohms |

L | Physical length | Dimensions | 1000 mil |

εeff | Effective dielectric constant | Unitless | 1.0 |

A | Attenuation per unit length | decibels | 0 dB/mil |

F0 | Frequency for attenuation factor | Frequency | 1000 MHz |

Model for a physical and lossy short circuited transmission line. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

TLINP4 - Physical 4 Node Transmission Line

Name | Description | Units | Default Value |

Z | Impedance | Resistance | 50 ohms |

L | Physical length | Dimensions | 1000 mil |

εeff | Effective dielectric constant | Unitless | 1.0 |

A | Attenuation per unit length | decibels | 0 dB/mil |

F0 | Frequency for attenuation factor | Frequency | 1000 MHz |

Model for a physical and lossy transmission line with the ground terminals left open and available as ports in the schematic. Electrical length of the transmission line is calculated at each simulated frequency using the user supplied physical length (L) and the effective dielectric constant (Eeff).

Loss per unit length is determined by the user supplied loss (A) and frequency for scaling (F0). If F0 is set to 0, then the loss per unit length is constant regardless of simulation frequency. Otherwise, the loss is scaled by the square root of the ratio of the simulation frequency and F0 (sqrt(f/F0)).

CLINP - Physical Coupled Transmission Line

Name | Description | Units | Default Value |

Zoe | Even-mode impedance | Resistance | 69 ohms |

Zoo | Odd-mode impedance | Resistance | 36 ohms |

L | Physical length | Dimensions | 1000 mil |

εeffE | Even-mode effective dielectric constant | Unitless | 1.0 |

εeffO | Odd-mode effective dielectric constant | Unitless | 1.0 |

AE | Even-mode attenuation per unit length | decibels | 0 dB/mil |

AO | Odd-mode attenuation per unit length | decibels | 0 dB/mil |

Model for a pair of lossy symmetric coupled transmission lines. Length is specified as a physical length(L). Coupling is determined by the even and odd mode impedances (Zoe and Zoo), effective dielectrics (EeffE and EeffO), and attenuation per unit length(AE and AO) over the specified physical length (L).

Given a desired coupling C in decibels, Zoe = Zo * ((1 + k) / (1 - k)) where k = power(10.0, -C/20.0). Zoo can the be found by solving Zoo = Zo * ((1 - k) / (1 + k))

Example: Find Zoe and Zoo for a 10 dB coupler in a 50 ohm system.

First calculate k as k = power(10.0, -10/20) = 0.316

Zoe is found as Zoe = Zo * ((1 + .316) / (1 - .316)) = 96.2 ohms

Zoo is found as Zoo = Zo * ((1 - .316) / (1 + .316)) = 26 ohms