A gasket-free electromagnetic shielding structure for 2.4 GHz band using folded quarter-wavelength SIW resonators

In recent years, various types of new shielding structures realizing shielding effectiveness (SE) at specific frequency band have been reported. A gasket-free shielding structure using cascaded substrate integrated waveguide (SIW) resonators is one of them. The structure consists of cascaded SIW resonators with different resonant frequencies placed on inner walls of a gap. Though the structure has an advantage of being almost free of deterioration due to its non-contact structure, miniaturization of the SIW resonators is necessary to be applied at several GHz bands. In this paper, a gasket-free shielding structure using folded quarter-wavelength (FQ)-SIW resonators is proposed and its SE is evaluated. An FQ-SIW resonator is a miniaturized SIW resonator by applying a multilayer substrate and modifying position of the coupling slits. A prototype configuration for 2.4 GHz band is designed and fabricated using a five-layered FR4 substrate. The designed FQ-SIW resonators are miniaturized to almost 1/7 of conventional SIW resonators, and the measured results of the cascaded configuration showed more than 30-dB improvement of SE at 2.4 GHz band.