# Lumped Element

A Lumped Element represents the RF lumped element available in the GUI. It defines a rectangular region where a selected network model sets the voltage-current relationship.

This object corresponds to tidy3d.rf.LinearLumpedElement (opens new window).

# Name

name: Unique name for the lumped element.

  • Required field

# Geometry

Specification of the lumped element region. The voltage axis must lie in the plane of the element.

# Center + Size

Object definition through a center position and size.

center: Center of the lumped element in x, y, and z-directions.

  • Type: floating-point number
  • Unit: m, mm (default in the RF GUI), um, or other available length unit
  • Default: (0, 0, 0)

size: Size of the lumped element in x, y, and z-directions.

  • Type: floating-point number
  • Unit: m, mm (default in the RF GUI), um, or other available length unit
  • Constraint: greater than or equal to 0
  • Required field

# Bounds

Object definition through minimum and maximum coordinate bounds.

min: Values of the x, y, and z coordinates defining the lower corner of the lumped element.

  • Type: floating-point number
  • Unit: m, mm (default in the RF GUI), um, or other available length unit
  • Required field

max: Values of the x, y, and z coordinates defining the upper corner of the lumped element.

  • Type: floating-point number
  • Unit: m, mm (default in the RF GUI), um, or other available length unit
  • Required field

# Settings

# Voltage Axis

voltage_axis: Axis along which the lumped element is oriented and along which the voltage drop occurs.

  • Options: X/Y/Z
  • Required field

NOTE

  • Set the voltage axis direction based on the direction of the physical voltage drop between terminals.

# Network

network: Network model that defines the voltage-current relationship of the lumped element.

type: Network model selected in the GUI.

  • Options: RLCNetwork, AdmittanceNetwork

See the network pages for the fields shown after a network type is selected.

# Advanced

# Distribution Type

dist_type: Distribution type used to place the network portion of the lumped element on the grid.

  • Options:
    • On: Distribute the network portion across the full lumped element bounding box.
    • Off: Restrict the network portion to one grid cell and use PEC connections to connect that cell to the edges of the lumped element.
    • Laterally only: Distribute the network portion only along the lateral axis of the lumped element.
  • Default: On

NOTE

Use On for most RF layouts. Use Off or Laterally only only when the network should not be distributed over the full bounding box, since the PEC connections can introduce additional parasitic series inductance and shunt capacitance.

Lumped element distribution type options

# Mesh

num_grid_cells: Number of mesh grid cells associated with the lumped element along each direction. These cells are used for automatic mesh refinement suggestions.

  • Type: integer
  • Constraint: greater than 0
  • Default: 1

snap_perimeter_to_grid: Toggle whether the perimeter of the lumped element is snapped to the simulation grid.

  • Options:
    • True: Snap the element perimeter to improve accuracy when the element contains a small number of grid cells.
    • False: Do not snap the element perimeter to the grid.
  • Default: True

enable_snapping_points: Toggle whether snapping points are automatically generated at key geometric features of the lumped element.

  • Options:
    • True: Generate snapping points for more accurate modeling.
    • False: Do not generate snapping points.
  • Default: True

NOTE

  • Keep snap_perimeter_to_grid and enable_snapping_points enabled for most RF layouts, especially when the element spans only a few grid cells.