Coupler Position Simulations
The full geometry of the position cavity was used in a lossy eigenmode computation to simulate the effects of moving the coupler. The full experimental results are at
ClicCouplerPosition
.
In simulation, the coupling is more sensitive to the feedthrough-waveguide spacing but the frequency is less sensitive. This may be due to the rounded ends of the feedthrough not being modelled accurately in simulation.
Low Conductivity and Lyapin Feedthrough
The simulations were repeated, once with a lower surface conductivity that brought the loaded Q down to the measured value and once with a bead at the end of the feedthrough.
Further work to understand these effects can be found
here
.
Mesh Dependence
The split in mode frequencies is due to the accuracy of the meshing. The dependence of the mode splitting and resonant frequency on mesh density is shown below. The accuracy is not sufficient for temperature simulations and so for these, the mesh will be made symmetric and dense and the solution may have to be third order.