Miniaturized substrate integrated waveguide symmetric filter with high selectivity

Abstract

A compact substrate integrated waveguide symmetric filter with source–load coupling using low temperature cofired ceramic (LTCC) technology for high-selectivity application is presented. The proposed filter with second-order resonators has two transmission zeros which can be controlled flexibly by adjusting the coupling strength and modifying coupling style. With the assistance of the multilayer LTCC structure and refined coupling manner, the proposed filter has a more compact size while maintaining high selectivity. A demonstration filter is designed, fabricated, and measured to validate the proposed structure. Measured results are provided to show good performance and in agreement with the simulated results. Moreover, thanks to the vertical LTCC multilayer structure, the overall size of the proposed filter is only  mm³.

Acknowledgments

This work was supported by the National Natural Science Foundation of China (Grant Nos.: 61101030 and 51172034) and Fundamental Research Funds for the Central Universities of China (Grant No.: ZYGX2011J132).