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I think you might want to explain a little more about what you are trying to model.

I've attached a very, very simple 2D model in the now rather-old Comsol version 3.5a of a radiating point source, at the default frequency of 1 GHz, at the center of a square, with simple scattering boundary conditions on all 4 edges. If you animate it, you can see an expanding pattern of rings moving away from the source, exactly as you would expect.

Question: What do you mean by saying you "tried to set the power source of LED as polarized Point dipole..." ? Why/how would anyone want to try to power an LED with a radiating dipole? Aren't LEDs (aka, light-emitting diodes) normally powered via electricity in directly-wired connections? Anyway, I hope the attached model helps. Good luck. And I also suggest you upgrade to a newer version of Comsol Multiphysics.

Robot,
Thank you very much for your reply , thanks for your file specially built for me, and I feel sorry for nor explaining the model clearly.
I tried to calculate the effects of photonic crystal on output efficiency of in LEDs. In published the paper, the light emiting layer source of dipole sources is suited for excitation, and it is always used as the radiating source of LED, in the file attached we can find that the circle is the dipole source, in this paper, the parameters of dipole source is :light wavelength is 465nm, full width at half maximum in 10nm,the absorption coefficient of GaN is 300cm-1 and photon lifetime is 320fs. I do not know how to set these parameters in Comsol. I tried to draw a point as the source but the point setting can only set the current.
I have not built models in Comsol for a period of time, so the version is old, thanks for your advice, and I will upgrade to the new version when this model is finished.
Last...I still can not open your file in my Comsol, I don not know why :(

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That helps me better understand your problem, but unfortunately, solid-state physics is not my field of expertise. Perhaps someone else reading this, who works on the design of LEDs (or similar semiconductor components) at the solid-state physics-level can help you. All the best.

Thank you, and all the best !