Lumped Port
Use the Lumped Port condition to apply a uniform electric field between two metallic boundaries. The excitation at the port can be expressed as a voltage or as a current, or via the connection to a circuit interface. The use of this feature is justified in frequency-domain studies when the distance between the metallic boundaries is much smaller than the wavelength of the electromagnetic radiation. Subject to the same requirements it can also be used in the time domain as a convenient way to excite a model.
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See About Lumped Ports and Lumped Port Parameters for more information.
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In the time domain, use the Magnetic and Electric Fields interface when the excitation has DC components or when the current conservation needs to be solved (for instance in modeling conducting fluids).
An operation named as Split by Connectivity () is available by right-clicking the parent node. The operation is useful when there are several lumped port boundaries that are not geometrically connected. Clicking the operation node will automatically generate several Lumped Port nodes where each selection is geometrically connected.
The geometry of the port is specified by the Type of lumped port. A Uniform lumped port applies a constant electric field between the metallic electrodes. A Coaxial lumped port applies a radial electric field between two concentric circular metallic boundaries. For these two cases, the dimension of the port is computed automatically by analyzing the geometry. Generally, select User defined to manually specify the direction between the lumped port terminals ah and the dimensions of the port: hport (Height of lumped port) and wport (Width of lumped port), both with SI unit: m.
For 2D components, a Uniform port applies an in-plane electric field. Therefore, the Uniform value is available for the Port type parameter only if the in-plane vector potential is solved for, according to the settings in the physics interface node. If the Components selected are Out-of-plane vector potential, the Uniform lumped port is not available.
For 2D axisymmetric components, the radial direction is in-plane with respect to the geometry. Therefore, the Coaxial value is available for the Port type parameter only if the in-plane vector potential is solved for, according to the settings in the physics interface node. If the Components selected are Out-of-plane vector potential, the Coaxial lumped port is not available.
For 2D and 2D axisymmetric components, if the Components selected in the physics interface is Out-of-plane vector potential, the dimension of the port cannot be obtained by analyzing the geometry and must be specified manually by the user. Therefore, User defined is the only option available for the Port type parameter. For this case the Direction between lumped port terminals is assumed to be in the out-of-plane direction and the input field is not available.
Lumped Port Properties
Enter a unique Lumped port name. It is recommended to use a numeric name as it is used to define the elements of the S-parameter matrix and numeric port names are also required for port sweeps and Touchstone file export.
Type of Lumped Port
The geometry of the port is specified by the Type of lumped port. A Uniform lumped port applies a constant electric field between the metallic electrodes. A Coaxial lumped port applies a radial electric field between two concentric circular metallic boundaries. For these two cases, the dimension of the port is computed automatically by analyzing the geometry.
Select a Type of lumped port — Uniform, Coaxial, User defined, or Via.
The Type of lumped port options available depend on the Components selected on the physics interface — Out-of-plane vector potential (the default), In-plane vector potential, or Three-component vector potential.
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For Out-of-plane vector potential the Type of lumped port is User defined.
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For In-plane vector potential or Three-component vector potential select a Type of lumped port — Uniform or User defined.
The Type of lumped port options available depend on the Components selected on the physics interface — Out-of-plane vector potential (the default), In-plane vector potential, or Three-component vector potential.
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For Out-of-plane vector potential the Type of lumped port is User defined.
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For In-plane vector potential or Three-component vector potential select a Type of lumped port — Coaxial or User defined.
Select User defined for nonuniform ports, for example, a curved port and enter values or expressions in the fields for these additional settings:
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Height of lumped port hport (SI unit: m)
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Width of lumped port wport (SI unit: m)
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A three-dimensional vector specifying the Direction between lumped port terminals ah (the direction of the applied electric field)
Select Via for excitation or termination of a cylindrical shape of a structure used in a metalized via that is a plated through hole.
Terminal Type
For all Types of lumped ports, select a Terminal type — Cable for a voltage driven transmission line, Current for a current driven port, or Circuit.
Wave Excitation at this Port
This section is available if Cable is selected as the Terminal type.
Select On or Off from the Wave excitation at this port list to set whether it is an inport or a listener port (connected to a passive transmission line). For On enter a Voltage V0 (SI unit: V), and Port phase θ (SI unit: rad) for the Voltage source type or enter a Power P0 (SI unit: W), that is the average input power to the lumped port, for the Power source type.
The section is deactivated if a Port sweep is active, since in this case the sweep controls the ports.
For the purpose of computing S-parameters, only one port at the time should be excited, for example by performing a Port sweep. In other cases, for example, when studying microwave heating, more than one inport might be desired, but in this case the S-parameter variables cannot be correctly computed. If several ports are excited at the same time, the S-parameter variables are not available for postprocessing.
Settings
This section is available if Cable or Current is selected as the Terminal type.
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For Cable enter the Characteristic impedance Zref (SI unit: Ω).
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For Current enter a current I0 (SI unit: A).