Substrate integrated folded waveguide controllable mixed electric and magnetic coupling structure and its application to millimetre-wave pseudo-elliptic filters

作者：Li, Xiang^*; You, Changjiang; Yu, Hongfang; He, Zhaosheng

来源：International Journal of RF and Microwave Computer-Aided Engineering, 2017, 27(4): e21074.

DOI：10.1002/mmce.21074

• bandpass filter
• high frequency selectivity
• millimeter-wave
• mixed coupling
• substrate integrated folded waveguide

A substrate integrated folded waveguide (SIFW) controllable mixed electric and magnetic coupling structure is proposed and investigated, which is suitable for millimeter-wave pseudo-elliptic filter applications. The proposed structure is built by a meandered slot-line (MSL) combined with an inductive via-hole in a SIFW cavity, which can support two closely-spaced resonator modes and achieves a mixed coupling. By adjusting the physical sizes of the mixed coupling structure, the electric and magnetic coupling can be separately controlled and a controllable transmission zero (TZ) can be produced below/above the passband. Furthermore, detailed analysis of the SIFW cavity mode spectrum and the mixed coupling characteristics are presented. Finally, direct-coupled and cross-coupled fourth-order pseudo-elliptic filters are designed, fabricated and measured to verify the proposed mixed coupling structure. The experimental results show that the proposed filters have good performance, such as high frequency selectivity, compact size, wide upper stopband, and easy integration with other planar circuits.

• 出版日期2017-5
• 单位电子科技大学