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Excitation of a CPW on infinite substrate

Hello,

I am trying to obtain the S-parameters of CPW line on an infinite substrate by calculating magnetic current rather than electrical current. I am using edge ports to achieve the results. However, my results are not correct. I have attached the layout for reference. Does anyone know how to resolve this issue? I am thinking that this is occurring due incorrect port definition but not sure.

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Feko

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Johan_Huysamen

Hi N_vasan

It is not exactly clear from your image how the feed section and edge port is defined so I am unable to comment on this.

For a simple way of feeding such a model, I would suggest using a wire 'bridge' across a gap as in the attached image. Here the wire bridges over the gap - connecting the two sections of the PEC layer. a wire port is then applied to this wire. The same is then done at the other end of the CPW section.

Regards,

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Altair Forum User

Hi Johan

I tried initially with wire port as you have suggested. However, the S-parameter values were not as expected. I am expecting S11 around -30dB, S21 < -1dB and a port impedance of 50 ohms. These values are obtained from HFSS simulations. However, when using the port or edge port along with Green's function I am getting S11 around -15dB and S21 around -0.48 dB at lower frequencies, -0.28dB at higher frequencies, and a port impedance of 1ohms to 5ohms.

I am unable to understand the reason for inaccurate results. Could you guide me?

Thank you

Johan_Huysamen

Dear N_vasan

Could you please share your FEKO model (CADFEKO CFX file)?

Regards,

Johan H

Altair Forum User

I have attached the file.

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