折叠半模基片集成波导在滤波器和均衡器中的应用

提出了一种数学建模方法用来分析折叠半模基片集成波导(FHMSIW)结构的场分布。基于多线理论首次计算了FHMSIW结构的衰减常数和相位常数，验证其与传统波导和基片集成波导的等效性。提出了FHMSIW结构具有高通特性和带阻特性，同时该结构的上下层具有近似奇对称的性质。通过在FHMSIW结构的中间金属层蚀刻缝隙或者添加金属过孔，就可以实现器件由带通到带阻的性能转换，给出了FHMSIW结构带阻、带通特性的产生和变换机理。利用其独特的性质，分别设计了等效HMSIW四分之一谐振枝节加载的FHMSIW均衡器和FHMSIW带通滤波器，设计的FHMSIW均衡器无需附加额外的馈电机制。测量结果显示出器件具有良好的性能，与仿真结果具有很好的一致性。相比于其他的平面电路，该设计的结构具有小型化、低损耗以及高Q值等优势。

Characteristic analysis of folded HMSIW and implements in equalizers and filters

A mathematical method is proposed to calculate the field distribution theoretically of folded half mode substrate integrated waveguide(FHMSIW) for the first time. The phase constant is also given using an improved multi-line method, verifying its equivalence with conventional waveguide and substrate integrated waveguides. The FHMSIW transmission line properties of resonance effect, quasi-rotational symmetry of two PCB layers and high-pass feature are proposed. An FHMSIW equalizer loaded equivalent HMSIW resonant cavities, and an FHMSIW bandpass filter loaded folded quarter-wave FHMSIW resonators are designed. The two components share the same structure with a little difference. The model analysis, simulated results and measured results are all provided. The FHMSIW equalizer is achieved without increasing extra excitation structures. The measured results show a good performance and are in agreement with the simulated results. Compared with the other planar circuits, these structures have superiorities of small size, simple structure, low loss and high Q, suitable for the miniaturization development, and are easily integrated with other circuits.