Study of monostatic vs bistatic RCS of metal object

abukarimabukarim Texas, USMember

Hi,

I created a PEC object of dimensions of 7.5cm x 7.5cm and 61 mil thickness and applied incident wave with theta between -180 to +180 deg and 1 deg step. Then surrounded the object with airbox then created boundary conditions of perf E for all airbox faces. I created 2 far fields for monostatic (phi & theta start=stop=step = 0deg) and bistatic (phi start=stop=step = 0 deg, theta start = -180, stop=180 deg and step = 1 deg). Then generate plots for monostatic and bistatic in dB. Monostatic plot looks good. Bistatic plot is wrong at forward-scattering area (i.e. when theta = -180 deg and +180 deg) in which the results came to be exactly monostatic values at those points. Technically Bistatic values at -180 deg and +180 deg at its lowest values compare to monostatic. Do you know why? can you provide any guidance on how to display forward scattering vs back scattering for both monostatic and bistatic modes.

Comments

  • jbommerjbommer TacomaMember

    Hi abukarim,

    I think the issue may be bistatic and monostatic plots are reporting RCS based on scattered and not total (incident + scattered) fields. For the condition you described it may be possible to see agreement between the theta = -180 (backscatter) and 0 (forward scatter) directions depending on the constructive/destructive currents that will get set up on the object. Since this may not be intuitive from the RCS plots for reasons described, you may get insight by plotting currents on the object and see the effect of changing Total/Scattered fields using "Edit Sources..." (right click "Excitations" node). Hope this helps, and apologies for the delay - I have been off this forum for some time.

  • I have the same problem. I computed the monostatic and bistatic RCS for a thin square plate, and got the same monostatic and bistatic values for both forward and backward scattering. I changed the total to the scattered fields for the "Excitations" node, but it didn't make any difference. Please advise.

  • rtkrtk Pune, IndiaForum Coordinator

    Hello @csl2019,

    The details on how to generate Monostatic and Bistatic plots and overlay them are available in the Help document. If the way you have plotted them is similar to the one in the HELP document do plot the current on the model and check whether they have anything model specific.

    As you have done the setting in the Edit sources, it should be because of the constructive/destructive currents on the model.



    Regards,

  • cslcsl Member

    It is not a matter of plotting. For the forward scattering, the bistatic RCS has to be different from the monostatic case. Would you respond why this is happening? I think there is a problem in the software.

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