Ask for help for generating finite width plane wave

Hi, recently,I am trying to use FDTD to simulated surface plasmon, after seting total field/scattered field for TE (Ex,Ey,Hz)model,I don't know how to introduce a finite width plane wave in the total field region. After the ordinary procedure to generate a plane wave at the vitural interface, the plane wave will full fill the total field region. Can anybody give me a idea of how to generate a finite width plane wave in the total region? thanks very much!

Just a thought: If I wanted to simulate a particular field but the software tool did not appear to support the distribution I would ask myself what type of structure would create the desired field?

I would then (try to) include that particular structure in the model. This may be a way to create the field you want for your evaluation.

If the front door is locked, sometimes you can get in the back way.

Good Luck.

That sounds like a really good idea,Thank you very much for your reply! I will try it.

Best wishes!

Does it really exists a finite width plane wave?
To be a approximately plane wave the width of the incident wave must be comparable to the width of the simulation area. That means the incident wave will full fill the simulation area.

Of course there can't be a true plane wave with finite width.

Why not use infinitely wide plane wave?

what i understad is that when you use the tf/sf formulation you are propagating a plane wave over the whole tf region... but i agree with the of Azulykit... you may want to model a structrure that would block some of the waves... but of course that should be wide enough not to encounter diffraction or some other phenomena...(just my thought)

apply a window function such as Gaussian profile to the source plane.