A novel low-loss suspended-line gap waveguide (SLGW) supporting transverse electromagnetic (TEM) propagation is presented for millimeter-wave applications for the first time. The suspended line is composed of two parallel strips connected by metal via holes. Periodic stacked-mushroom electromagnetic band gap (SM-EBG) structures are used to package the suspended line by creating a stopband for all parallel-plate modes. According to the different packaging requirements of the circuit, the SM-EBG unit cell can be composed of several stacked mushrooms and metal covers. The air gaps’ thickness between face-to-face patches of the adjacent mushrooms is near zero, confining more power in the air-filled guiding region of the SLGW. Furthermore, the SM-EBG structures with near-zero thick air gaps can provide more stable mechanical support for the multilayer structure. Therefore, SLGW has a lower loss and more robust gap stability compared with the conventional air-filled printed versions of GWs, such as printed ridge gap waveguide (PRGW) and inverted microstrip gap waveguide (IMGW). On the other hand, compared with the self-packaged double-sided interconnected strip line (DSISL), the proposed SLGW packaged with SM-EBG structures has the advantage of no electrical contact, avoiding the power leakages in the gap between plates at discontinuities and simplifying the assembly. The design and analysis of the SM-EBG structure, the design of SLGW, and the microstrip-to-SLGW transition design are given in this article. A prototype of the proposed SLGW with back-to-back transition is fabricated packaged with SM-EBG structures to prove the concept.

中文翻译：

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新颖的悬挂式间隙波导与堆叠式蘑菇EBG结构封装在一起

首次针对毫米波应用提出了一种新型的支持横向电磁（TEM）传播的低损耗悬浮线间隙波导（SLGW）。悬挂线由通过金属通孔连接的两个平行带组成。周期性的叠蘑菇电磁带隙（SM-EBG）结构用于通过为所有平行板模式创建阻带来包装悬挂线。根据电路的不同包装要求，SM-EBG单元电池可以由几个堆叠的蘑菇和金属盖组成。相邻蘑菇的面对面贴片之间的气隙厚度接近零，从而在SLGW的充满空气的引导区域内限制了更多功率。此外，具有接近零厚度的气隙的SM-EBG结构可以为多层结构提供更稳定的机械支撑。因此，与传统的GW充气印刷版本（例如印刷脊形间隙波导（PRGW）和倒置微带间隙波导（IMGW））相比，SLGW的损耗更低，间隙稳定性更强。另一方面，与自包装的双面互连带状线（DSISL）相比，所建议的SLGW封装的SM-EBG结构具有无电接触的优势，避免了不连续的板之间间隙中的功率泄漏和简化组装。本文给出了SM-EBG结构的设计和分析，SLGW的设计以及微带到SLGW的过渡设计。