为了实现太赫兹高斯光束与双曲线形金属波导的高效耦合, 设计了一个渐变的椭圆-双曲线形金属波导连接器。此波导连接器的输入端是矩形的, 输出端是椭圆-双曲线形的。在渐变的过程中, 矩形金属波导的TE01模逐渐转变成双曲线形金属波导的椭圆偏振模。根据WKB近似, 这个缓慢渐变的波导消除了反射和散射, TE01模和椭圆偏振模的耦合效率可以高达94%。最终, 经过这个渐变连接器, 高斯光束和双曲线形金属波导的耦合效率可以提高到69.1%。

In order to couple a terahertz Gaussian beam into a hyperbolic metal waveguide(HMWG), a tapered elliptical-hyperbolic metal waveguide(TEHMWG) was proposed as a connector. The input of the TEHMWG was rectangular, and the output was elliptical-hyperbolic. In the tapered process, the TE01 mode of rectangular metal waveguide was gradually transformed into the elliptical polarized mode of hyperbolic metal waveguide. According to WKB approximation, the slowly tapered waveguide eliminated the reflection and scattering. The coupling efficiency between the TE01 mode and the elliptical polarized mode was 94%. Through this connector, the coupling efficiency between a Gaussian beam and HMWG was improved to 69.1%.