ComPhys @comphys@qoto.org

Small update to the TEM mode analysis with #FEniCS example.

I've added in a calculation for the mutual capacitance and self-inductance per unit length of the transmission line.

https://comphysblog.wordpress.com/2018/09/06/tem-mode-analysis-with-fenics/

#opensource #physics #python #ham

I've just finished my new post: TEM mode analysis with #FEniCS an #opensource finite element differential equation solver. https://comphysblog.wordpress.com/2018/09/06/tem-mode-analysis-with-fenics/

In this post I calculate the electric and magnetic fields on a coaxial cable, characteristic impedance of the line, the Poynting vector, the conductor and dielectric loss, an estimated loss coefficient, Q-factor and s-parameter for a given length of cable.

Coax has been a useful example for comparisons with analytical results but the methods are very general. TEM modes of systems with different geometries can also be analysed with the exact same techniques!

Very happy to hear any comments, corrections or suggestions.

#physics #ham #python

Starting my next post which will be about the TEM mode on a two-conductor transmission line. Specifically I'll be looking at a coaxial geometry and using #FEniCS to calculate the field distributions, the characteristic impedance and the Poynting vector. Just had a go and it all seems to be working.

While I'll focus on a coaxial geometry the method can be extended to more complicated geometries just by changing the mesh & boundaries. I've just had a go at an odd mode impedance and it came out just right!

The best thing about this post will be how easy it is.

#physics #electromagnetism #HAM #radio #Maxwell #opensource #python

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Does the \LaTeX support work?

I use wxmaxima as a mathematica alternative. I don't consider it to be as polished as mathematica but in general it's pretty amazing.

The syntax of sympy puts me off (too much like programming) and I find sage to be a bit too huge and clunky.

What computer algebra systems does everybody else use?

3D electrostatics example using #FEniCS. In this example I solve the Laplace equation for two concentric spheres to obtain an electric potential and take the gradient to find the electric field. The results are then compared with an analytical solution.

The geometry is produced in FreeCAD and the mesh/ boundaries produced with Gmsh.

https://comphysblog.wordpress.com/2018/08/26/3d-electrostatics-using-fenics/

Please let me know if you have comments or corrections!

#physics #electromagnetism #opensource #python