## GRE9277 #34

polaritons
Posts: 2
Joined: Sat Sep 03, 2011 1:41 pm

### GRE9277 #34

This question asks about conducting cavity driven as an electromagnetic resonator.

I have never heard of conducting cavity before, so I was not familiar with that. Well now I know the boundary condition for a conducting cavity. But can someone give a physical explanation of what a conducting cavity is and how do we get the boundary conditions?

Also, what is an electromagnetic resonator?

Thanks.

Chiron
Posts: 9
Joined: Tue Sep 01, 2015 10:37 am

### Re: GRE9277 #34

I realize that this is an old post, but I will post in the hope it helps someone else who is studying.

In terms of a conducting cavity, you can just think about any cavity where the surrounding walls are composed entirely of a perfect conductor.

The boundary conditions for a perfect conductor are as follows
$$\vec{E^{\|}_2} - \vec{E^{\|}_1} = 0\\[\tex] \vec{D^{\perp}_2} - \vec{D^{\perp}_1} = \sigma$$$$$\vec{B^{\perp}_2} - \vec{B^{\perp}_1} = 0$$$
$$\vec{H^{\|}_2} - \vec{H^{\|}_1} = \vec{k} \times \vec{n} \hspace{1cm} where \vec{k}$$$is electric current density and$\vec{n}\$ is a vector normal to the surface