R/Q Measurements of Multi-Gap Metamaterial Extended Interaction Resonant Cavity Using Perturbation Method

In this paper, the $\boldsymbol{R/Q}$ measurement method of a metamaterial extended interaction resonant cavity (MEIRC) is investigated using the perturbation method. The $\boldsymbol{R/Q}$ expression for MEIRC is accordingly given, which depends on the natural frequency $\boldsymbol{f_{0}}$ of the MEIRC, the perturbation frequency shift $\Delta f$ , and the structural parameters. The $\boldsymbol{R/Q}$ expression is verified by CST simulation where a PTFE dielectric cylinder is considered as the perturbed body. After fabrication and assembly of the MEIRC, the measured natural frequency $\boldsymbol{f_{0}}$ of the double-gap MEIRC is 2.427 GHz, with an $\boldsymbol{R/Q}$ of 182.5 $\Omega$ and an $\boldsymbol{R/Q}$ error of 1.5% relative to the simulated one. In addition, the measured natural frequency $\boldsymbol{f_{0}}$ of the three-gap MEIRC is 2.443 GHz, $\boldsymbol{R/Q}$ is 286.0 $\boldsymbol{\Omega}$ , and the $\boldsymbol{R/Q}$ error is 5.7% relative to the simulated one. The measurements reported here pave the path for developing the metamaterial extended interaction devices.