一种基于SIW的阶梯式太赫兹宽带传输线

提出了一种适用于太赫兹频段、长距离传输的阶梯式宽带传输线。将2个基片集成波导(substrate integrated waveguide, SIW)分别置于一个矩形波导两端并分别呈直角转接,整个结构组成一级阶梯形状以实现波导口的空间位置平移。通过在矩形波导两端使用耦合窗的方法完成空气与基片介质之间无模式转换的转接。所提出的阶梯式传输线不仅能够承载宽带太赫兹波传输,而且能够实现传输线入口和出口的波场出射方向不变。仿真结果表明,在从SIW到矩形波导再到SIW的结构中,波导具有良好的传输性能,其中在WR-4.3波段,传输的相对带宽为54%,S11参数值小于-10 dB,传输线插入损耗在190～230 GHz频率范围内小于1.2 dB。因此,所提出的传输线可用于太赫兹波的远距离传输,并为解决太赫兹多站成像系统中的器件尺寸与波长级的成像中心距离之间的矛盾提供了参考。

A stair-stepped transmission line based on SIW for terahertz wide-band transmission

This paper presents a stair-stepped transmission line for terahertz wide-band transmission that contains two substrate integrated waveguides (SIW). Two SIW parts locate at both ends of a rectangular waveguide that form two steps to achieve spatial position translation of the waveguide port. The interconnection of the contained SIW to the waveguide based on the coupled window-based structure achieves a vertical and mode-free transfer and ensures the wide-band characteristics of the transmission. Thus, the proposed stair-stepped transmission line is not only capable of carrying wide-band terahertz waves for transmission, but also realizes a constant direction of wave-field emission at the input and output of the transmission line due to the small size of the SIW. The simulation results show that the waveguide has good transmission performance in the structure from SIW to rectangular waveguide and then back to SIW, achieving 54% of the transmission relative bandwidth in the WR-4.3 band, the reflection coefficient, less than -10 dB, and transmission line loss is less than 1.2 dB in the frequency range of 190-230 GHz. Therefore, the proposed transmission line can be used for the long-distance transmission of terahertz waves. On the other hand, in a terahertz multi-station imaging system, our proposed transmission line provides the possibility to solve the contradictory between the device sizes and wavelength-level imaging phase center.