基于3 dB 定向耦合器的0.14 THz 功率分配器设计方法

介绍了一种基于3 dB 定向耦合器的0.14 THz 功率分配器设计方法。由于太赫兹频段的器件尺寸越来越小型化、微型化，特别是对于功率分配器中的核心结构，造成精密机械加工方式难以实现。典型的波导3 dB 定向耦合器结构是90电桥结构，其耦合缝隙之间的间距仅有不到0.5 mm，这样的尺寸是机加时产生的应力难以承受的。通过分析波导定向耦合器支路间的相位关系得出:如果耦合缝隙的间距增加到半波长的整数倍，支路间的相位差仍为90，但这样变化的结果是带宽的降低。通过耦合缝隙间距的适度增加，降低了机加的难度，工作相对带宽降到10%。经仿真分析，结果得到了验证。加工的样品测试结果表明，在0.133 ~0.147 THz 的频率范围内，插入损耗小于1 dB，回波损耗小于-20 dB。

Design method about 0.14 THz power divider based on 3 dB directional coupler

A design new method about 0.14 THz power divider based on 3 dB directional coupler was presented. As THz device's dimension is micro -miniature, especially the key structure such as power divider's, it is extraordinary difficult to fabricate by precise machining. Traditional 3 dB directional coupler has 90 electric bridge structure, whose length between coupler slots is only less than 0.5 mm. This size nearly cannot bear the machining stress in processing. By means of analyzing the phase relationship between the direction coupler's branches, it is known that if the length between coupler slots increases only half-wave length's integer-multiple, the phase contrast between branches is still 90. As a result, the bandwidth is sacrificed. Since the dimension of coupling slot increases, this structure makes precise machining easy, and it has a band width about 10% at least yet. Analysis of simulation result provides the verification. The measured insert loss from 0.133 THz to 0.147 THz is less than 1 dB, and the return loss is less than -20 dB.