Periodic cylinder filled up metamaterial

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Dear All,

 

I have an issue concerning the use of “Double NeGative” (DNG) metamaterials. The issue regards the electromagnetic scattering of plane waves from DNG metamaterial cylinders

 

I firstly considered an indefinite (along the z axis), homogeneous cylinder having radius = 4lambda in the case of normally incident plane wave with TM polarization at f = 300MHz (see Fig. 1 in attached files). The cylinder is filled up with a DNG metamaterial having eps_r= -2.2, while mu_r<0 changes from case to case. An indefinite cylinder has been obtained with periodic boundary conditions.
The result from FEKO is compared with a cylindrical wave expansion (see “Normal Incidence Plane Wave Scattering by Conducting Circular Cylinder: TMzPolarization” – Advanced Engineering Electromagnetic, Constantine A. Balanis).
FEKO and the cylindrical wave expansion agree for mu_r =-1 (see Fig. 2) and for mu_r = -1.2 (see Fig. 3), while they disagree for mu_r= -1.3 and mu_r = -1.5 (see Fig. 4 and Fig. 5).
Please, find attached the related .cfx file and relative figures.

 

Thank you very much for any help.

<?xml version="1.0" encoding="UTF-8"?>Fig. 1 - cilindro vista alto.JPG

<?xml version="1.0" encoding="UTF-8"?>Fig. 2 - cfr_metacyl_DNG_epsr_22_mur_1_.jpg

<?xml version="1.0" encoding="UTF-8"?>Fig. 3 - cfr_metacyl_DNG_epsr_22_mur_12_.jpg

<?xml version="1.0" encoding="UTF-8"?>Fig. 4 - cfr_metacyl_DNG_epsr_22_mur_13_.jpg

<?xml version="1.0" encoding="UTF-8"?>Fig. 5 - cfr_metacyl_DNG_epsr_22_mur_15_.jpg

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Answers

  • Mel
    Mel Altair Community Member
    edited June 2019

    Hi Zerk

     

    We can't find anything wrong with your model.

     

    Regarding the far fields, Feko gives the spherical far field, while you might be comparing with a cylindrial far field which is dependent on 1/sqrt(r)

    Perhaps a better idea would be to compare the near fields a sufficient distance away from the structure.

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