Quadri-Folded Substrate Integrated Waveguide Cavity and Its Miniaturized Bandpass Filter Applications

Abstract

In this paper, a quadri-folded substrate integrated waveguide (QFSIW) resonant cavity is proposed and investigated for the first time, which is able to reduce the circuit size by 89% compared with the conventional substrate integrated waveguide (SIW) resonant cavity. It has a two-layer configuration and a C-type coupling slot etched on the middle conductor layer. As an example, such a miniaturized resonant cavity is employed in the design of a four-order S-band SIW bandpass filter with the Chebyshev response. Negative couplings are used between two adjacent SIW resonant cavities, which don't influence the whole transmission characteristic of the filter. Experimental results are in good agreement with those from simulations.

Miniaturization Trends in Substrate Integrated Waveguide (SIW) Filters: A Review

“…The authors of [46] used a quadri-folded SIW (QFSIW) for the first time to reduce the SIW dimensions by 89% of the conventional SIW structures. Figure.…”

“…Coupling between the vertically connected resonators is optimized using a C-shaped slot in the middle copper layer. The concept of such coupling topology and miniaturization technique is verified by designing a fourth-order SIW bandpass filter [46].…”

“…Inductive and capacitive loading in an SIW plays important role in shifting the fundamental resonant mode to the lower [46]. FIGURE 9: Stub-loaded vertically-and horizontally-coupled filters [48].…”

Compact Substrate Integrated Waveguide Filtering Antennas: A Review

“…Firstly, for studying the miniaturization of the SIW FA, we compare several methods of the miniaturization of the SIW filter. In the process of the SIW filter miniaturization, the SIW is firstly folded to form a multi-layer structure [39]- [41]. Then, a particular structure is etched on the top metal layer to form inductive and capacitive loading.…”

Design and Analysis of Ridge Substrate Integrated Waveguide Bandpass Filter With Octagonal Complementary Split Ring Resonator for Suppression of Higher Order Harmonics

“…The latest trend in wireless communication system needs miniaturized filters in association with integrated multifunctional and multiband accomplishment for suppressing interference. It has been demonstrated that ring resonator based filters have attractive behaviour [2][3][4], but they have certain drawbacks such as large dimension and existence of higher order mode. Microstrip lines are compact and less expensive but resulting in non-immunity to the losses and parasitic crosstalk between lines.…”