Dipole Frequency Selective Surface

中文/English

The Ansoft designer results are take from :

1. Yang, F., J. Chen, R. Qiang, and A. Elsherbeni (2007), A simple and efficient FDTD/PBC algorithm for scattering

analysis of periodic structures, Radio Sci., 42, RS4004, doi:10.1029/2006RS003526.

2. Elsherbeni and Demir – The Finite-Difference Time-Domain Method for Electromagnetics

with MATLAB. Simulations, 2nd Edition (2015)



Example results and CAD download

Example_DFSS_Theta180

Example_DFSS_Theta150

Example_DFSS_Theta120

Example_DFSS_Theta180_Phi21.3

Example_DFSS_Theta0_Phi21.3

https://mega.nz/#!ap0zGAjb!PdOooi6LCTBo_r3KPho66ODWdU2qBJkF4_ZhgkfHYbg

*.FCstd is the save file of FreeCAD


Add the boundary of the CAD files (FreeCAD)

Reference : 3D-CAD Simulation & Examples 


Comparison & Reference：
1. Yang, F., J. Chen, R. Qiang, and A. Elsherbeni (2007), A simple and efficient FDTD/PBC algorithm for scattering
analysis of periodic structures, Radio Sci., 42, RS4004, doi:10.1029/2006RS003526.
2. Elsherbeni and Demir – The Finite-Difference Time-Domain Method for Electromagnetics
with MATLAB. Simulations, 2nd Edition (2015)


Define Parameters

A.Main-Setup

1. Selected the simulation dimension.

2. Define total x, y, z length that equal to CAD, and then set a appropriate resolution.

3. Import CAD files.

4. Define the material of each CAD.

5. Press【建立網格 Cad to Grids (Create)】button to create simulation grids.


B.Boundary Conditions


A. Define the boundary conditions

B. Press the【創建 (Create)】button => Create the total grid size (Include the boundary condition & add space)

C.Wave & Observation

The incident wave is linear polarization in y axis (pis=90) from upper side(theta =180).

Reflection Spectrum observation : + Z direction

Transmission Spectrum observation : - Z direction

instruction webpage: DFT (Observation Range)

C. Import the metal layer, due to the PCB metal layer thickness << delta (dz)

==> using the "Load Wire (*.stl)" function

Patch_patch.stl

E. Geometries. Design


Checked out the simulation geometries, and then press 【輸出 Output】button to output the geometries files

Data_Materials.csv // (simulation index of structures)

Other simulation files refer to below figures:

F.Spectrum & Field Pattern

1. Set the Spectrum Analysis & Wavelength range

2. Check out the source

G.Calculation

1. Set the simulation time setp

2. Save parameters

3. Calculation

H.Result Analysis

★(Result Analysis)：

頻譜 (Spectrum) : Analysis the spectrum

This is TE (Polar 1) polarization results, The symbol means:

p1 : polarization 1

Py: Poynting (intensity)

real: real part

co : co-polar (coefficient)

cross : cross-polar (coefficient)


Overall means the total energy, here the incident source is normalized to 1

Overall-p1-Py-real

Overall : Transmission (intensity)+ reflection (intensity) = 1 (energy conservation for without loss)


Transmission-p1-Py-real : Transmission intensity : T

Reflection-p1-Py-real : Reflection intensity : R


The relationship of transmission intensity of co-polar, cross polar are

Transmission-p1-co = co-polar : |t-co|, which is polarization direction same to incident source

Transmission-p1-cross = co-polar: |t-cross|, which is polarization direction orthogonal (90 degrees) with incident source


T (intensity) = |t-co|^2+|t-cross|^2

R (intensity) = |r-co|^2+|r-cross|^2


The relationship of these


Overall =1= T (intensity)+ R (intensity) = |t-co|^2+|t-cross|^2 + |r-co|^2+|r-cross|^2


TM, LHCP, RHCP are the same

For the oblique incident 150 degrees (30 degrees in paper), 120 degrees(60 degrees in paper) results:


The simulation examples download:

Example_DFSS_Theta180

Example_DFSS_Theta150

Example_DFSS_Theta120

https://mega.nz/#!ap0zGAjb!PdOooi6LCTBo_r3KPho66ODWdU2qBJkF4_ZhgkfHYbg





=====================================

==== Example 2 ====

=====================================



in ref.(2), Chapter 14

2. Elsherbeni and Demir – The Finite-Difference Time-Domain Method for Electromagnetics

with MATLAB. Simulations, 2nd Edition (2015)


The condition : Kx=20 radian/meter, Ky= 7.8 radian/meter



Method 1 : use periodic boundary condition

Kx=20 radian/meter, Ky= 7.8 radian/meter


and then the phi= atan2(Ky,Kx) = 21.3058 degree


set Phi = 21.3 degrees, and the other are all the same


The simulation examples download:

Example_DFSS_Theta180_Phi21.3

https://mega.nz/#!ap0zGAjb!PdOooi6LCTBo_r3KPho66ODWdU2qBJkF4_ZhgkfHYbg

The default define z- is port 1, z+ is port 2, and the relation between T&R and S-parameter as shown in figure.

From up (z+) side incident (source from port 2, theta =180 degree) can get S12, S22 co-polar and cross-polar


if we want get the Scattering parameters S11 and S21, then need to run another simulation that from z- side (source from port 1, theta =0 degree) incident


download Example_DFSS_Theta0_Phi21.3

https://mega.nz/#!ap0zGAjb!PdOooi6LCTBo_r3KPho66ODWdU2qBJkF4_ZhgkfHYbg

and then get