Study of effective permittivity and loss reduction of SISL using ring resonator.

A ring resonator used to study the effective permittivity and the loss of substrate integrated suspended line (SISL) is presented in this article. The effective permittivity is obtained by calculating resonant frequency and the relative value of loss is calculated by comparing unloaded quality factor (Q factor). For the four cases of uniform ring resonators, their S‐parameter, effective permittivity, unloaded Q factors are simulated, measured and investigated. The effect caused by the height of air cavity, the material of dielectric substrate, dielectric loss tangent is also investigated. Finally, the calculated results indicate that the effective permittivity of SISL structure at operating frequency is very closed to 1, which manifests that within a certain substrate‐material range the relative permittivity of substrate has little influence on SISL platform that is instructive for SISL circuits design. And the use of metalized via‐hole connection with dielectric removal can reduce the circuit loss dramatically. [ABSTRACT FROM AUTHOR]