Hello!
I am testing COMSOL with a simple 2D model of a waveguide for the TE10 mode (physics: transient electromagnetic waves, study: time dependent), i am using the scattering boundary condition for the entry and exit of the wave.
When the waveguide depth is a multiple of the wavelength, the solution converges to the analytical solution after a few cycles, but when it's not, no matter how small the element size or the time step are, it will converge to a solution with an error in amplitude (in same cases very high, the amplitude I am imposing is E0= 1 V/m, and somethimes it converges to an amplitude of E0=1.4 V/m). I have tested for smaller and longer waveguides but the conclusion was always the same. Anyone has an explanation for this?
I have attached four images, two with the evolution of the amplitude in a point in the middle of the waveguide (one where the wavelength is a multiple of the waveguide's depth, and another where it isn't), and two with the respective electric fields.
I am testing COMSOL with a simple 2D model of a waveguide for the TE10 mode (physics: transient electromagnetic waves, study: time dependent), i am using the scattering boundary condition for the entry and exit of the wave.
When the waveguide depth is a multiple of the wavelength, the solution converges to the analytical solution after a few cycles, but when it's not, no matter how small the element size or the time step are, it will converge to a solution with an error in amplitude (in same cases very high, the amplitude I am imposing is E0= 1 V/m, and somethimes it converges to an amplitude of E0=1.4 V/m). I have tested for smaller and longer waveguides but the conclusion was always the same. Anyone has an explanation for this?
I have attached four images, two with the evolution of the amplitude in a point in the middle of the waveguide (one where the wavelength is a multiple of the waveguide's depth, and another where it isn't), and two with the respective electric fields.