Transmission Line (CE)

The model of the transmission line.

blockType: SubSystem

Path in the library:

/RF/Circuit Envelope/Elements/Transmission Line (CE)

Description

Block Transmission Line (CE) simulates transmission lines with delay, lumped parameters, and distributed transmission. The block parameters are automatically changed depending on the selected model type.

Ports

Conserving

# 1+ — the first electrical port
electricity

Details

The electrical port corresponding to the positive terminal of the RF circuit.

Program usage name

1+

# 1- — the first electrical port
electricity

Details

The electrical port corresponding to the negative terminal of the RF circuit.

Program usage name

1-

# 2+ — the second electrical port
electricity

Details

The electrical port corresponding to the positive terminal of the RF circuit.

Program usage name

2+

# 2- — the second electrical port
electricity

Details

The electrical port corresponding to the negative terminal of the RF circuit.

Program usage name

2-

Parameters

# Model type: — transmission line model
Lumped parameter L-section | Lumped parameter Pi-section

Details

The type of transmission line model specified as one of the following options.

Types of transmission lines Description

Types of transmission lines	Description
`Lumped parameter L-section`	A model of an L-section RLGC transmission line.
`Lumped parameter Pi-section`	A transmission line model with RLGC pi sections.

Lumped parameter L-section

A model of an L-section RLGC transmission line.

transmission line ce 1

Lumped parameter Pi-section

A transmission line model with RLGC pi sections.

transmission line ce 2

Values	`Lumped parameter L-section` \| `Lumped parameter Pi-section`
Default value	`Lumped parameter L-section`
Program usage name	`model_type`
Tunable	No
Evaluatable	Yes

# Parameterization: — the type of parameters for modeling segments in a transmission line
By characteristic impedance and capacitance | By inductance and capacitance

Details

The type of parameters for modeling segments in a power line, set as By characteristic impedance and capacitance or By inductance and capacitance.

Values	`By characteristic impedance and capacitance` \| `By inductance and capacitance`
Default value	`By characteristic impedance and capacitance`
Program usage name	`parametrization`
Tunable	No
Evaluatable	Yes

# Characteristic impedance, Ohm: — transmission line impedance

Details

The impedance of the transmission line, given as a real scalar in ohms.

Dependencies

To use this parameter, set for the parameter Parameterization: meaning By characteristic impedance and capacitance.

Default value	`50`
Program usage name	`ch_impedance`
Tunable	No
Evaluatable	Yes

# Resistance per unit length, Ohm/m: — resistance per unit length of transmission line

Details

The resistance per unit length of the transmission line, set as a positive scalar in ohms/m.

Dependencies

To use this parameter, set for the parameter Parameterization: meaning By characteristic impedance and capacitance.

Default value	`0.3`
Program usage name	`resistance_per_unit_length`
Tunable	No
Evaluatable	Yes

# Inductance per unit length, H/m: — inductance per unit length of transmission line

Details

The inductance per unit length of the transmission line, set as a positive scalar in Gn/m.

Dependencies

To use this parameter, set for the parameter Parameterization: meaning By inductance and capacitance.

Default value	`2.35e-7`
Program usage name	`inductance_per_unit_length`
Tunable	No
Evaluatable	Yes

# Capacitance per unit length, F/m: — capacity per unit length of transmission line

Details

Capacity per unit length of the transmission line, set as a positive scalar in Ft/m.

Default value	`94e-12`
Program usage name	`capacitance_per_unit_length`
Tunable	No
Evaluatable	Yes

# Conductance per unit length, S/m: — conductivity per unit length of transmission line

Details

The conductivity per unit length of the transmission line, given as a positive scalar in S/m.

Default value	`5e-6`
Program usage name	`conductance_per_unit_length`
Tunable	No
Evaluatable	Yes

# Line length, m: — physical length of the transmission line

Details

Physical length of the transmission line , defined as a positive scalar in M.

Default value	`1e-2`
Program usage name	`line_length`
Tunable	No
Evaluatable	Yes

# Number of segments: — number of segments in the transmission line

Details

The number of segments in the transmission line, set as a positive scalar.

Default value	`10`
Program usage name	`num_segments`
Tunable	No
Evaluatable	Yes

Additional Info

Calculation of distributed transmission line parameters

Details

When modeling distributed transmission lines, the block first calculates the ABCD parameters on a set of internal frequencies. The ABCD parameters are converted to S-parameters for simulation.

The block calculates the ABCD parameters based on the physical length of the transmission line and a comprehensive continuous distribution using the following set of equations:

where — the specified characteristic impedance.

Literature

Sussman-Fort, S. E., and J. C. Hantgan. «SPICE Implementation of Lossy Transmission Line and Schottky Diode Models.» IEEE Transactions on Microwave Theory and Techniques. Vol. 36, No.1, January 1988.
Pozar, David M. Microwave Engineering. Hoboken, NJ: John Wiley & Sons, Inc., 2005.
Gupta, K. C., Ramesh Garg, Inder Bahl, and Prakash Bhartia. Microstrip Lines and Slotlines, 2nd Edition, Norwood, MA: Artech House, Inc., 1996.
Ludwig, Reinhold and Pavel Bretchko. RF Circuit Design: Theory and Applications. Englewood Cliffs: NJ: Prentice-Hall, 2000.
True, Kenneth M. «Data Transmission Lines and Their Characteristics.» National Semiconductor Application Note 806, April 1992.