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How to set boundary condition to obtain extreme electric field on the boundary?
Posted 10 févr. 2025, 21:09 UTC−5 RF & Microwave Engineering Version 6.1 2 Replies
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Hello sir,
I met a problem while simulating the coaxial line. I want to analyze different modes of the electromagnetic wave transporting in it. In some certain conditions, I need to set boundary conditions on the both ends of the coaxial line so that the electric field reach its extreme value at the ends. Take an example, for the 1/4 lambda coaxial waveguide for length L, one end can be PEC so the electric field is zero at that end. Could you please tell me how to set boundary condition for the other end, which can successfully simulate the modes Esin(kx), where k=n*pi/2L.
best wishes
Cai
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Sounds like you want to use the RF module, frequency domain, with an eigenfrequency-type study, with a short circuit (a PEC) at one end of your coax and an open circuit (lumped coaxial port with a nearly-infinite impedance) at the other. Be sure to set the solver to look in the vicinity of the resonant frequencies of interest. I just tried that and it worked fine. See the attached image, showing 3 separate solutions (leverages the "array plot" feature). Plot is of the radial component of E. (I would include the .mph file, but I have a more recent version of Comsol Multiphysics than you.)
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Please login with a confirmed email address before reporting spam
Sounds like you want to use the RF module, frequency domain, with an eigenfrequency-type study, with a short circuit (a PEC) at one end of your coax and an open circuit (lumped coaxial port with a nearly-infinite impedance) at the other. Be sure to set the solver to look in the vicinity of the resonant frequencies of interest. I just tried that and it worked fine. See the attached image, showing 3 separate solutions (leverages the "array plot" feature). Plot is of the radial component of E. (I would include the .mph file, but I have a more recent version of Comsol Multiphysics than you.)
It works. Thank you sir, it helps a lot.