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How to construct an infinitely long, z-directed electric line current source in Feko?

XH2026

Hi, I am learning how to compute the 2D scattering using MoM with the surface equivalence principle (SEP) and a 1D periodic boundary condition (PBC) in Feko.

I would like to know whether it is possible to construct an infinitely long, z-directed electric line current source located at $(x_s,y_s)$, $\mathbf{J}(\mathbf{r})=I \delta (x-x_s) \delta (y-y_s) \hat{\mathbf{z}}$, to serve as the excitation source. The corresponding incident field is described by the two-dimensional Green's function, $G (\mathbf{r}, \mathbf{r}^{\prime}) =-\frac{j}{4} H_0^{(2)} (k_0 |\mathbf{r}-\mathbf{r}^{\prime}|)$.

If this type of source is supported in Feko, could you please advise how to define it? If not, is there an alternative approach to approximate or realize this excitation in FEKO?

Thank you very much for your time and assistance.

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Accepted answers

Jaehoon

Hello @XH2026,

As the error message said, the impressed current source is not compatible with the PBC.

So I'd like to suggest you to draw a long cylinder and an impressed current source as below.

I also changed the solver to MLFMM.

Please see the attached model..and check the current source's phase behavior is what you want with its radiated electric and magnetic fields.

Best regards,

Jaehoon

impressed-current-2d-scattering_mod.zip

All comments

Jaehoon

Hello @XH2026,

To construct an infinitely long current source, I would like to suggest using the impressed current source in Feko as shown below.

Please refer to the user guide about the source.

And please check the field with Near-field request.

Best regards,

Jaehoon

XH2026

Hi Jaehoon,

Thank you for your suggestion. However, it appears that the impressed current source cannot be combined with a 1D PBC to construct an infinitely long electric line current source. The output file reports "ERROR 32784: Unsupported source type used with periodic boundaries".

Best regards,

XH2026

Jaehoon

Hello @XH2026,

I didn't recognize you want to include the impressed current source inside the PBC. Sorry.

I'd like to clearly understand what your target simulation is.

Could you share your Feko model (.cfx) which generates the error 32784?

Let me see if any other source works as an infinite line current or it is possible without an 1D PBC?

Best regards,

Jaehoon

XH2026

Hi @Jaehoon,

Please review the attached file. I would like to compute a 2D electromagnetic scattering problem in FEKO, where an infinitely long electric line current source is used as the excitation. I am using the MoM with a 1D PBC, but the impressed current source cannot be used in combination with the PBC.

Thank you.

Best regards,

XH2026

Impressed_Current_2D_Scattering.cfx

XH2026

Hi @Jaehoon,

Thank you very much for your help. Extending the 3D object sufficiently in the z-direction and computing the fields on a single cross-sectional plane can provide a good approximation to the corresponding 2D problem. However, for multiple electrically large scatterers, this approach becomes computationally expensive. It seems that FEKO may not be the most suitable tool for this type of 2D analysis, so I will probably explore other full-wave simulation software.

Thank you again for your time and assistance!

Best regards,

XH2026

Jaehoon

Hello @XH2026,

Let me check with our developer about how to include the current source or equivalent in the PBC.

Please wait some time.

Best regards,

Jaehoon