New cable modeling features in Feko - Part 2
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3. Shielded enclosure MoM/MTL feature
The shielded enclosure is a specialisation of the schematic link and was first developed and then the schematic link generalised the connections to the full wave geometry.
Figure 13: Shielded enclosure component represented in the Graphical User Interface (GUI).
As the name suggests, the cable bundle shield connections must be to a fully enclosed metallic enclosure and the shields must be shorted to the enclosure. The enclosure effectively is a continuation of the cable shield. The cable signals connecting to each other and/or networks inside the enclosure are non-radiating. This allows for better representation of the radiation / irradiation of the cable assembly as the shield currents can now continue along the outer surface of the shielded enclosure. Figure 14 represents a coaxial assembly connecting to a two-way power divider inside a metallic enclosure and Figure 15 shows the associated cable schematic.
Figure 14: 3D view of a coaxial cable assembly connecting to a shielded enclosure with a two-way power divider network inside the enclosure.
Figure 15: Cable schematic setup with the power divider assembly of Figure 14.
The Shielded enclosure option is computationally more efficient compared to the Schematic link option and is a good option when high quality shielded connectors are used to connect to a fully enclosed shielded enclosure. The cable assembly of Figure 14 can also be represented with the schematic link. However, with the schematic link formulation non-ideal shield connections can be modeled (as non-radiating circuits or as full wave geometry) and the enclosure need not to be closed, see Figure 16.
Figure 16: Extending the shielded enclosure power divider model of Figure 14 with the schematic link to have full wave non-ideal connectors. The power divider is modeled as a general network in the full wave domain.
Figure 17: Transformer and Voltage Controlled Voltage Source (VCVS) cable schematic components.
These components can be used to model transfer impedance over a connector shield. Meaning, current leaking from inside of the shield to the outside of the shield at the connector and vice versa. However, the user must provide / estimate the transfer impedance (coupling factor) across the connector shield. With the Schematic Link feature, it is now much easier to model the effect of non-ideal connectors and pig-tail connections without approximation.
References
[1] C.R. Paul, Analysis of Multiconductor Transmission Lines, 2nd ed., Wiley-Interscience, 2008.