Radar Cross Section (RCS) simulation of a triangular corner reflector

Altair Forum User
Altair Forum User
Altair Employee
edited August 2022 in Community Q&A

Hi everyone,

i'm trying to simulate a pretty simple layout for verification reasons:

The layout consists of a triangular corner reflector with the length of the inner edge to the corner of 0.5m.

I'm calculating at 5.7GHz and search for the Radar Cross Section (RCS).

In order to calculate the RCS I've added a plane wave along the X-Axis and a Far Field Request with varying configurations (which all returned the same result).

The RCS seems to be (according to Feko) roughly 82m2, but the Formula i've been using has been giving me 94m2 which is closer to what we've measured (a bit more than 100m2 at boresight).

 

σ = 4·π·a4 where a = Length of the side edges of the three isosceles triangles
λ = wavelength of scanning Radar 		(7)
3·λ2

(Source: http://www.radartutorial.eu/17.bauteile/bt47.en.html)

Am i making any fundamental mistakes in my calculations or simulations?

Greetings

Cupacoffee

<?xml version="1.0" encoding="UTF-8"?>tri.png

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Answers

  • JIF
    JIF
    Altair Employee
    edited June 2018

    Hello Cupacoffee,

     

    Do you mind adding your model? I know it is easy for me to re-create, but if you add it, I don't have to. ;-)

  • Johan_Huysamen
    Johan_Huysamen
    Altair Employee
    edited June 2018

    Hi Cupacoffee

     

    I believe that the corner reflector as described in your reference should have 90 degree internal angles. Your screen shot from CADFEKO does not appear to show 90 degree angles.

     

    You should check to ensure that this geometry is correct.

     

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited November 2020
    Altair Forum User said:

    Hello Cupacoffee,

     

    Do you mind adding your model? I know it is easy for me to re-create, but if you add it, I don't have to. ;-)

    I've uploaded the model. Thanks for looking into the issue.

     

    Altair Forum User said:

    Hi Cupacoffee

     

    I believe that the corner reflector as described in your reference should have 90 degree internal angles. Your screen shot from CADFEKO does not appear to show 90 degree angles.

     

    You should check to ensure that this geometry is correct.

     

    As can be seen in the screenshot all inner angles appear to be 90°, you can verify with the model aswell.

     

    Greetings

     

    Cupacoffee

    <?xml version="1.0" encoding="UTF-8"?>it_is_90 .png

    Unable to find an attachment - read this blog

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2018

    I've figured out the source of the problem myself: The boresight of the Reflector was not aligned properly as can be seen in the screenshot.

    I had a ~ 10° offset which explains the low value. The new value of 102.5m nicely lines up with the measurements we conducted.

     

    Thanks to everyone who looked into the issue.

    <?xml version="1.0" encoding="UTF-8"?>Angle_Error.png

  • Eric Neumann
    Eric Neumann Altair Community Member
    edited August 2022
    Altair Forum User said:

    I've figured out the source of the problem myself: The boresight of the Reflector was not aligned properly as can be seen in the screenshot.

    I had a ~ 10° offset which explains the low value. The new value of 102.5m nicely lines up with the measurements we conducted.

     

    Thanks to everyone who looked into the issue.

    <?xml version="1.0" encoding="UTF-8"?>Angle_Error.png

    Hello Altair Forum User,

     

    can you tell me which value you changed to 102.5m to achieve the correct boresight? Did you rotate the whole thing?

     

    Thanks in advance :)

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