Wang Juan Lin Yihua Dec 25th,2010 Discussion of resonant cavity and the simulation by software COMSOL

Content 1.Theoretical deduction of TM wave function 2.Practical simulation of TE & TM wave in resonant cavity by COMSOL 3.Some interesting questions in the process of simulation

I. Theoretical deduction

According to: Z=0: Z=d: I. Theoretical deduction

Resonance frequency: In a cubical resonant cavity: Define: Discussion of degree of degeneracy: 1., the degree of degeneracy is 1; 2., the degree of degeneracy is 3; 3., the degree of degeneracy is 6;

TE (0,1,1) Mode: II. Practical simulation

Section: z=0 a=0, b=1 Section: y=0 a=0, c=1 Section: x=0 b=1, c=1 II. Practical simulation

Section: y=0 a=0, c=1 II. Practical simulation

TE (2,1,1) Mode: Section: y=0 a=2, b=1 II. Practical simulation

Calculating the power flow:

The power flow in TE (2,1,1) Mode: II. Practical simulation

Problem 1 1. When simulating electrical density in COMSOL:

The power density in the pipe is 2~3 ranges larger than that in the resonant cavity: Key point

Solution

There exists a “power hole” in the process of simulating electrical density: Problem 2

Key point The sub sources interfered the inner distribution of electric density! Then the challenge comes: 1. How to smooth the edges to avoid the occurrence of sub sources? 2.How to “break” the symmetry of the wave source to avoid the same phase position?

Solution 1. How to smooth the edges to avoid the occurrence of sub sources?

Solution 2.How to “break” the symmetry of the wave source to avoid the same phase position?

The result: Solution

Having known how to take advantage of simulation software to test the theoretical result; Try to think hard to find ways to eliminate all the problems when putting the model into practice! Conclusion

Thanks!