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Help Modeling Radiating Waveguide + Receiving Antenna

Natalia Nigay Beamed Microwave Propulsion

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Hi all,

The goal of my simulation is to determine the electric field intensity at specific locations in the receving antenna (simple conical structure). The power comes from a circular waveguide some distance away. Right now, I am thinking of using a 2D, axisymmetric model using the RF module setting the input port with power input of 1 kW at the far end of the cylinder I will use to model the waveguide.

I will define the metallic materials of the structures and set them as PEC and use a scattering boundary condition.

Is this a correct way of approaching the problem? I have never done a simulation with the input power coming from a separate structure (always had a coaxial port directly feeding my structure of interest), so I do not want to get this wrong. Is there any fundamental part that I am missing in the setup?

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Natalia

2 Replies Last Post Jan 14, 2023, 11:09 a.m. EST
Edgar J. Kaiser Certified Consultant

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Posted: 2 years ago Jan 14, 2023, 9:59 a.m. EST

Natalia,

you might consider to use a PML to supress reflections from the model boundary.

Cheers, Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Natalia, you might consider to use a PML to supress reflections from the model boundary. Cheers, Edgar

Robert Koslover Certified Consultant

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Posted: 2 years ago Jan 14, 2023, 11:09 a.m. EST
Updated: 2 years ago Jan 14, 2023, 11:25 a.m. EST

I encourage you to provide a picture of your geometry. How is your waveguide arranged and oriented relative to your antenna? You mention wanting to do a 2D, axisymmetric model. But is the combination of your antenna and waveguide axisymmetric? You say the waveguide is "some distance away." Is it close enough for local fields to couple to your antenna? Is it far enough away that your antenna might as well be being illuminated by a plane wave? If so, might you prefer to compute your waveguide generated fields separately and ignore local mutual coupling effects between the waveguide and antenna? You say that you are using a circular waveguide. What mode are you using to feed the waveguide? Is this waveguide mode consistent with your plan to use a 2D axisymmetric model? FYI, the "Comsol Application Library" contains examples of 3D antennas modeled using 2D axisymmetric models. I refer specifically to the "conical_horn_lens_antenna" and the "corrugated_circular_horn_antenna". You might want to take a look at those.

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
I encourage you to provide a picture of your geometry. How is your waveguide arranged and oriented relative to your antenna? You mention wanting to do a 2D, axisymmetric model. But is the *combination* of your antenna and waveguide axisymmetric? You say the waveguide is "some distance away." Is it close enough for local fields to couple to your antenna? Is it far enough away that your antenna might as well be being illuminated by a plane wave? If so, might you prefer to compute your waveguide generated fields separately and ignore local mutual coupling effects between the waveguide and antenna? You say that you are using a circular waveguide. What mode are you using to feed the waveguide? Is this waveguide mode consistent with your plan to use a 2D axisymmetric model? FYI, the "Comsol Application Library" contains examples of 3D antennas modeled using 2D axisymmetric models. I refer specifically to the "conical_horn_lens_antenna" and the "corrugated_circular_horn_antenna". You might want to take a look at those.

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