Excitation of wispering gallery mode in resonator

[yefj]

Hello,I have built a resonator which needs to produce whispering gallery mode and coupled threw coaxial cables .
I got a mode at 9.87z and at 11.29Ghz.
But its coupling is very low .
How can I increase the coupling to this mode?
Thanks.
2025-05-21 12-38-37.mkv

 

[Baluncore]

But its coupling is very low .
How can I increase the coupling to this mode?

I assume you are referring to coupling of the input cable, and output cable, to the cavity. Better coupling may reduce the Q of the cavity.

You show the shield entering into the cavity with only a small probe exposed. How did you select those dimensions?

I would consider removing the shield and connecting the tip of the probe to the wall. That would form a small coupling loop antenna.

 

[yefj]

Hello,Could you please draw what you mean in general?
How down it helpes with achieving good coupling?

 

[Baluncore]

Hello,Could you please draw what you mean in general?

(a) If you use a loop, you are coupling with the magnetic field.
(b) If you use a probe, you are coupling with an electric field.

How down it helpes with achieving good coupling?

Higher currents can be induced in the cavity walls. Depending on the orientation of the loop, you can excite different modes of resonance.

 

[sophiecentaur]

Better coupling may reduce the Q of the cavity.

Ain't that always the way? Good coupling implies a matched load which will produce a low Q. A high Q system must only pass a small amount of power. It's horses for courses I would say.

How can I increase the coupling to this mode?

Do you mean to minimise insertion loss? That would imply matching the source and load. There are a lot of variables, I think.